Desert Ops

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FM 90-3

MCWP 3-35.6 (formerly FMFM 7-27)

Desert Operations

U.S. Marine Corps

PCN 14300012600


2/223

MCCDC (C 42)

15 Sept 2004

E R R A T U M

to

MCWP 3-35.6

DESERT OPERATIONS

1. For administrative purposes, the publication short title has been reidentified. ChangeFMFM

7-27to readMCWP 3-35.6wherever it appears in the Manual. Also, change the PCN,

13900067500, to 14300012600.


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FM 90-3

CHAPTER 1

THEENVIRONMENT

AND ITS EFFECTSON PERSONNELAND EQUIPMENT

This chapter describes the desert environment and how it affects personnel andequipment.

CONTENTS

Page

Section I The Environment . . . . . . . . . . . . . . . . . . 1-1

Section II Environmental Effects onPersonnel . . . . . . . . . . . . . . . . . . . . . . . . 1-17

Section III Environmental Effects onEquipment . . . . . . . . . . . . . . . . . . . . . . . 1-30

Section I. The Environment

Successful desert operations require adaptation to the environment and to thelimitations its terrain and climate impose. Equipment and tactics must bemodified and adapted to a dusty and rugged landscape where temperatures varyfrom extreme highs down to freezing and where visibility may change from 30miles to 30 feet in a matter of minutes. Deserts are arid, barren regions of theearth incapable of supporting normal life due to lack of water. See Figure 1-1forarid regions of the world. Temperatures vary according to latitude and season,from over 136 degrees Fahrenheit in the deserts of Mexico and Libya to the bittercold of winter in the Gobi (East Asia). In some deserts, day-to-night temperaturefluctuation exceeds 70 degrees Fahrenheit. Some species of animal and plant life

have adapted successfully to desert conditions where annual rainfall may varyfrom O to 10 inches.

Desert terrain also varies considerably from place to place, the sole commondenominator being lack of water with its consequent environmental effects, suchas sparse, if any, vegetation. The basic land forms are similar to those in otherparts of the world, but the topsoil has been eroded due to a combination of lack

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of water, heat, and wind to give deserts their characteristic barren appearance.The bedrock may be covered by a flat layer of sand, or gravel, or may have beenexposed by erosion. Other common features are sand dunes, escarpments, wadis,and depressions. This environment can profoundly affect military operations.

SeeFigure 1-2 for locations of major deserts of the world, andAppendix A foradditional information on desert countries of the world.

It is important to realize that deserts are affected by seasons. Those in theSouthern Hemisphere have summer between 21 December and 21 March. This6-month difference from the United States is important when consideringequipping and training nonacclimatized soldiers/marines for desert operationssouth of the equator.

TERRAINKey terrain in the desert is largely dependent on the restrictions to movement thatare present. If the desert floor will not support wheeled vehicle traffic, the fewroads and desert tracks become key terrain. Crossroads are vital as they controlmilitary operations in a large area. Desert warfare is often a battle for control ofthe lines of communication (LOC). The side that can protect its own LOC whileinterdicting those of the enemy will prevail. Water sources are vital, especially if

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a force is incapable of long distance resupply of its water requirements. Defilesplay an important role, where they exist. In the Western Desert of Libya, anescarpment that paralleled the coast was a barrier to movement except through afew passes. Control of these passes was vital. Similar escarpments are found in

Saudi Arabia and Kuwait.

Types of Desert Terrain

There are three types of desert terrain: mountain, rocky plateau, and sandy ordune terrain. The following paragraphs discuss these types of terrain.

Mountain Deserts

Mountain deserts are characterized by scattered ranges or areas of barren hills ormountains, separated by dry, flat basins. SeeFigure 1-3for an example of

mountain desert terrain. High ground may rise gradually or abruptly from flatareas, to a height of several thousand feet above sea level. Most of the infrequentrainfall occurs on high ground and runs off in the form of flash floods, erodingdeep gullies and ravines and depositing sand and gravel around the edges of thebasins. Water evaporates rapidly, leaving the land as barren as before, althoughthere may be short-lived vegetation. If sufficient water enters the basin tocompensate for the rate of evaporation, shallow lakes may develop, such as theGreat Salt Lake in Utah or the Dead Sea; most of these have a high salt content.

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FM 90-3

Rocky Plateau Deserts

Rocky plateau deserts are extensive flat areas with quantities of solid or brokenrock at or near the surface. See Figure 1-4 for an example of a rocky plateaudesert. They may be wet or dry, steep-walled eroded valleys, known as wadis,gulches, or canyons. Narrow valleys can be extremely dangerous to men andmateriel due to flash flooding after rains; although their flat bottoms may besuperficially attractive as assembly areas. The National Training Center and theGolan Heights are examples of rocky plateau deserts.

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Sandy or Dune Deserts

Sandy or dune deserts are extensive flat areas covered with sand or gravel, theproduct of ancient deposits or modern wind erosion. Flat is relative in thiscase, as some areas may contain sand dunes that are over 1,000 feet high and10-15 miles long; trafficability on this type of terrain will depend onwindward/leeward gradients of the dunes and the texture of the sand. See Figure1-5 for an example of a sandy desert. Other areas, however, may be totally flatfor distances of 3,000 meters and beyond. Plant life may vary from none toscrub, reaching over 6 feet high. Examples of this type of desert include the ergsof the Sahara, the Empty Quarter of the Arabian desert, areas of California andNew Mexico, and the Kalahari in South Africa. See Figure 1-6 for an exampleof a dune desert.

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Trafficability

Roads and trails are rare in the open desert. Complex road systems beyondsimple commercial links are not needed. Road systems have been used for

centuries to connect centers of commerce, or important religious shrines such asMecca and Medina in Saudi Arabia. These road systems are supplemented byroutes joining oil or other mineral deposits to collection outlet points. Somesurfaces, such as lava beds or salt marshes, preclude any form of routinevehicular movement, but generally ground movement is possible in alldirections. Speed of movement varies depending on surface texture.Rudimentary trails are used by minor caravans and nomadic tribesmen, withwells or oases approximately every 20 to 40 miles; although there are somewaterless stretches which extend over 100 miles. Trails vary in width from a fewmeters to over 800 meters.

Vehicle travel in mountainous desert country may be severely restricted.Available mutes can be easily blinked by the enemy or by climatic conditions.

Hairpin turns are common on the edges of precipitous mountain gorges, and thehigher passes may be blocked by snow in the winter.

Natural Factors

The following terrain features require special considerations regardingtrafficability.

Wadis or dried water courses, vary from wide, but barely perceptible depressionsof soft sand, dotted with bushes, to deep, steep-sided ravines. There frequently isa passable route through the bottom of a dried wadi. Wadis can provide cover

from ground observation and camouflage from visual air reconnaissance. Thethreat of flash floods after heavy rains poses a significant danger to troops andequipment downstream. Flooding may occur in these areas even if it is notraining in the immediate area. See Figure 1-7 for an example of a wadi.

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Salt marsh (sebkha) terrain is impassable to tracks and wheels when wet. Whendry it has a brittle, crusty surface, negotiable by light wheel vehicles only. Saltmarshes develop at points where the water in the subsoil of the desert rose to thesurface. Because of the constant evaporation in the desert, the salts carried bythe water are deposited, and results in a hard, brittle crust.

Salt marshes are normally impassable, the worst type being those with a dry crustof silt on top. Marsh mud used on desert sand will, however, produce anexcellent temporary road. Many desert areas have salt marshes either in thecenter of a drainage basin or near the sea coast. Old trails or paths may cross themarsh, which are visible during the dry season but not in the wet season. In thewet season trails are indicated by standing water due to the crust being too hardor too thick for it to penetrate. However, such routes should not be tried byload-carrying vehicles without prior reconnaissance and marking. Vehicles maybecome mired so severely as to render equipment and units combat ineffective.Heavier track-laying vehicles, like tanks, are especially susceptible to theseareas, therefore reconnaissance is critical.

Man-made Factors

The ruins of earlier civilizations, scattered across the deserts of the world, oftenare sited along important avenues of approach and frequently dominate the onlyavailable passes in difficult terrain. Control of these positions maybe imperativefor any force intending to dominate the immediate area. Currently occupieddwellings have little impact on trafficability except that they are normally locatednear roads and trails. Apart from nomadic tribesmen who live in tents (seeFigure 1-8 for an example of desert nomads), the population lives in thick-walled structures with small windows, usually built of masonry or a mud andstraw (adobe) mixture.Figure 1-9 shows common man-made desert structures.

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Because of exploration for and production of oil and other resources, wells,pipelines, refineries, quarries, and crushing plants may be of strategic importancein the desert. Pipelines are often raised 1 meter off the groundwhere this is thecase, pipelines will inhibit movement. Subsurface pipelines can also be anobstacle. In Southwest Asia, the subsurface pipelines were indicated on maps.Often they were buried at such a shallow depth that they could be damaged by

heavy vehicles traversing them. Furthermore, if a pipeline is ruptured, not onlyis the spill of oil a consideration, but the fumes maybe hazardous as well.

Agriculture in desert areas has little effect on trafficability except that canalslimit surface mobility. Destruction of an irrigation system, which may be a resultof military operations, could have a devastating effect on the local populationand should be an important consideration in operational estimates. Figure 1-10shows an irrigation ditch.

TEMPERATURE

The highest known ambient temperature recorded in a desert was 136 degreesFahrenheit (58 degrees Celsius). Lower temperatures than this produced internaltank temperatures approaching 160 degrees Fahrenheit (71 degrees Celsius) inthe Sahara Desert during the Second World War. Winter temperatures inSiberian deserts and in the Gobi reach minus 50 degrees Fahrenheit (minus 45degrees Celsius). Low temperatures are aggravated by very strong windsproducing high windchill factors. The cloudless sky of the desert permits the

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earth to heat during sunlit hours, yet cool to near freezing at night. In the inlandSinai, for example, day-to-night temperature fluctuations are as much as 72degrees Fahrenheit.

WINDS

Desert winds can achieve velocities of near hurricane force; dust and sandsuspended within them make life intolerable, maintenance very difficult, andrestrict visibility to a few meters. The Sahara Khamseen, for example, lasts fordays at a time; although it normally only occurs in the spring and summer. The

deserts of Iran are equally well known for the wind of 120 days, with sandblowing almost constantly from the north at wind velocities of up to 75 miles perhour.

Although there is no danger of a man being buried alive by a sandstorm,individuals can become separated from their units. In all deserts, rapidtemperature changes invariably follow strong winds. Even without wind, thetelltale clouds raised by wheels, tracks, and marching troops give awaymovement. Wind aggravates the problem. As the day gets wanner the windincreases and the dust signatures of vehicles may drift downwind for severalhundred meters.

In the evening the wind normally settles down. In many deserts a prevailingwind blows steadily from one cardinal direction for most of the year, andeventually switches to another direction for the remaining months. Theequinoctial gales raise huge sandstorms that rise to several thousand feet andmay last for several days. Gales and sandstorms in the winter months can bebitterly cold. SeeFigure 1-11for an example of wind erosion.

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Sandstorms are likely to form suddenly and stop just as suddenly. In a severesandstorm, sand permeates everything making movement nearly impossible, notonly because of limited visibility, but also because blowing sand damages

moving parts of machinery.

WATER

The lack of water is the most important single characteristic of the desert. Thepopulation, if any, varies directly with local water supply. A Sahara oasis may,for its size, be one of the most densely occupied places on earth (seeFigure 1-12for a typical oasis).

Desert rainfall varies from one day in the year to intermittent showers throughoutthe winter. Severe thunderstorms bring heavy rain, and usually far too much rainfalls far too quickly to organize collection on a systematic basis. The water soonsoaks into the ground and may result in flash floods. In some cases the rainbinds the sand much like a beach after the tide ebbs allowing easy maneuverhowever, it also turns loam into an impassable quagmire obstacle. Rainstormstend to be localized, affecting only a few square kilometers at a time. Wheneverpossible, as storms approach, vehicles should move to rocky areas or highground to avoid flash floods and becoming mired.

Permanent rivers such as the Nile, the Colorado, or the Kuiseb in the NamibDesert of Southwest Africa are fed by heavy precipitation outside the desert sothe river survives despite a high evaporation rate.

Subsurface water may be so far below the surface, or so limited, that wells arenormally inadequate to support any great number of people. Because potablewater is absolutely vital, a large natural supply may be both tactically andstrategically important. Destruction of a water supply system may become apolitical rather than military decision, because of its lasting effects on theresident civilian population.

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Finding Water

When there is no surface water, tap into the earths water table for ground water.Access to this table and its supply of generally pure water depends on thecontour of the land and the type of soil. See Figure 1-13 for water tables.

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From Rocky Soil

Look for springs and seepages. Limestone has more and larger springs than anyother type rock. Because limestone is easily dissolved, caverns are readilyetched in it by ground water. Look in these caverns for springs. Lava rock is agood source of seeping ground water because it is porous. Look for springsalong the walls of valleys that cross the lava flow. Look for seepage where a drycanyon cuts through a layer of porous sandstone.

Watch for water indicators in desert environments. Some signs to look for arethe direction in which certain birds fly, the location of plants, and theconvergence of game trails. Asian sand grouse, crested larks, and zebra birdsvisit water holes at least once a day. Parrots and pigeons must live within reachof water. Cattails, greasewoods, willows, elderberry, rushes, and salt grass growonly where ground water is near the surface. Look for these signs and dig. Ifyou do not have a bayonet or entrenching tool, dig with a flat rock or sharp stick.

Desert natives often know of lingering surface pools in low places. They covertheir surface pools, so look under brush heaps or in sheltered nooks, especially insemiarid and brush country.

Places that are visibly damp, where animals have scratched, or where flies hover,indicate recent surface water. Dig in such places for water. Collect dew on clearnights by sponging it up with a handkerchief. During a heavy dew you should beabIe to collect about a pint an hour.

Dig in dry stream beds because water may be found under the gravel. When insnow fields, put in a water container and place it in the sun out of the wind.

From Plants

If unsuccessful in your search for ground or runoff water, or if you do not havetime to purify the questionable water, a water-yielding plant may be the bestsource. Clear sap from many plants is easily obtained. This sap is pure and ismostly water.

Plant tissues. Many plants with fleshy leaves or stems store drinkablewater. Try them wherever you find them. Thebarrel cactus of the southwestern

United States is a possible source of water (seeFigure 1-14). Use it only as a lastresort and only if you have the energy to cut through the tough, spine-studdedouter rind. Cut off the top of the cactus and smash the pulp within the plant.Catch the liquid in a container. Chunks may be carried as an emergency watersource. A barrel cactus 3-1/2 feet high will yield about a quart of milky juice andis an exception to the rule that milky or colored sap-bearing plants should not beeaten.

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Roots of desert plants. Desert plants often have their roots near the surface.The Australian water tree, desert oak, and bloodwood are some examples. Prythese roots out of the ground, cut them into 24-36 inch lengths, remove the bark,and suck the water.

Vines. Not all vines yield palatable water, but try any vine found. Use thefollowing method for tapping a vine--it will work on any species:

Step 1. Cut a deep notch in the vine as high up as you can reach.Step 2. Cut the vine off close to the ground and let the water drip into your

mouth or into a container.Step 3. When the water ceases to drip, cut another section off the top.

Repeat this until the supply of fluid is exhausted.

Palms. Burl, coconut, sugar and nipa palms contain a drinkable sugaryfluid. To start the flow in coconut palm, bend the flower stalk downward and cut

off the top. If a thin slice is cut off the stalk every 12 hours, you can renew theflow and collect up to a quart a day.

Coconut. Select green coconuts. They can be opened easily with a knifeand they have more milk than ripe coconuts. The juice of a ripe coconut isextremely laxative; therefore, do not drink more than three or four cups a day.

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The milk of a coconut can be obtained by piercing two eyes of the coconut with asharp object such as a stick or a nail. To break off the outer fibrous covering ofthe coconut without a knife, slam the coconut forcefully on the point of a rock orprotruding stump.

Survival Water Still

YOU can build a cheap and simple survival still that will produce drinking waterin a dry desert. Basic materials for setting up this still are--

6-foot square sheet of clean plastic.

A 2- to 4-quart capacity container.

A 5-foot piece of flexible plastic tubing.

Pick an unshaded spot for the still, and dig a hole. If no shovel is available, use a

stick or even your hands. The hole should be about 3 feet across for a few inchesdown, then slope the hole toward the bottom as shown in Figure 1-15 whichdepicts a cross section of a survival still. The hole should be deep enough so thepoint of the plastic cone will be about 18 inches below ground and will still clearthe top of the container. Once the hole is properly dug, tape one end of theplastic drinking tube inside the container and center the container in the bottomof the hole. Leave the top end of the drinking tube free, lay the plastic sheet overthe hole, and pile enough dirt around the edge of the plastic to hold it securely.Use a fist-size rock to weight down the center of the plastic; adjust the plastic asnecessary to bring it within a couple of inches of the top of the container. Heatfrom the sun vaporizes the ground water. This vapor condenses under theplastic, trickles down, and drops into the container.

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VEGETATION

The indigenous vegetation and wildlife of a desert have physiologically adaptedto the conditions of the desert environment. For example, the cacti of theAmerican desert store moisture in enlarged stems. Some plants have

drought-resistant seeds that may lie dormant for years, followed by a brief, butcolorful display of growth after a rainstorm. The available vegetation is usuallyinadequate to provide much shade, shelter, or concealment, especially from theair. Some plants, like the desert gourd, have vines which grow to 4.5 meters (15feet). Others have wide lateral roots just below the surface to take advantage ofrain and dew, while still others grow deep roots to tap subsurface water.Presence of palm trees usually indicates water within a meter of the surface, saltgrass within 2 meters, cottonwood and willows up to 4 meters. In addition toindicating the presence of water, some plants are edible.

WILDLIFE

Invertebrates such as ground-dwelling spiders, scorpions, and centipedes,together with insects of almost every type, are in the desert. Drawn to man as asource of moisture or food, lice, mites, and flies can be extremely unpleasant andcarry diseases such as scrub typhus and dysentery. The stings of scorpions andthe bites of centipedes and spiders are extremely painful, though seldom fatal.Some species of scorpion, as well as black widow and recluse spiders,death. The following paragraphs describe some of the wildlifeencountered in desert areas and the hazards they may pose to man.

Scorpions

can causethat are

Scorpions are prevalent in desert regions.

particularly active at night. Scorpions are

They prefer damp locations and are

easily recognizable by their crab-likeappearance, and by their long tail which ends in a sharp stinger. Adult scorpionsvary from less than an inch to almost 8 inches in length. Colors range fromnearly black to straw to striped. Scorpions hide in clothing, boots, or bedding, sotroops should routinely shake these items before using. Although scorpion stingsare rarely fatal, they can be painful.

Flies

Flies are abundant throughout desert environments. Filth-borne disease is amajor health problem posed by flies. Dirt or insects in the desert can cause

infection in minor cuts and scratches.

Fleas

Avoid all dogs and rats which are the major carriers of fleas. Fleas are theprimary carriers of plague and murine typhus.

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Reptiles

Reptiles are perhaps the most characteristic group of desert animals. Lizardsand snakes occur in quantity, and crocodiles are common in some desert rivers.Lizards are normally harmless and can be ignored; although exceptions occur inNorth America and Saudi Arabia.

Snakes, ranging from the totally harmless to the lethal, abound in the desert. Abite from a poisonous snake under two feet long can easily become infected.Snakes seek shade (cool areas) under bushes, rocks, trees, and shrubs. Theseareas should be checked before sitting or resting. Troops should always checkclothing and boots before putting them on. Vehicle operators should look forsnakes when initially conducting before-operations maintenance. Look forsnakes in and around suspension components and engine compartments assnakes may seek the warm areas on recently parked vehicles to avoid the coolnight temperatures,

Sand vipers have two long and distinctive fangs that may be covered with acurtain of flesh or folded back into the mouth. Sand vipers usually areaggressive and dangerous in spite of their size. A sand viper usually buries itselfin the sand and may strike at a passing man; its presence is alerted by acharacteristic coiling pattern left on the sand.

The Egyptian cobra can be identified by its characteristic cobra combativeposture. In this posture, the upper portion of the body is raised vertically and thehead tilted sharply forward. The neck is usually flattened to form a hood. TheEgyptian cobra is often found around rocky places and ruins and is fairlycommon. The distance the cobra can strike in a forward direction is equal to the

distance the head is raised above the ground. Poking around in holes and rockpiles is particularly dangerous because of the likelihood of encountering a cobra.See Figure 1-16 for an example of a viper and cobra.

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Mammals

The camel is the best known desert mammal. The urine of the camel is veryconcentrated to reduce water loss, allowing it to lose 30 percent of its bodyweight without undue distress. A proportionate loss would be fatal to man. The

camel regains this weight by drinking up to 27 gallons (120 liters) of water at atime. It cannot, however, live indefinitely without water and will die ofdehydration as readily as man in equivalent circumstances. Other mammals,such as gazelles, obtain most of their required water supply from the vegetationthey eat and live in areas where there is no open water. Smaller animals,including rodents, conserve their moisture by burrowing underground away fromthe direct heat of the sun, only emerging for foraging at night. All these livingthings have adapted to the environment over a period of thousands of years;however, man has not made this adaptation and must carry his food and waterwith him and must also adapt to this severe environment.

Dogs are often found near mess facilities and tend to be in packs of 8 or 10.

Dogs are carriers of rabies and should be avoided. Commanders must decidehow to deal with packs of dogs; extermination and avoidance are two options.Dogs also carry fleas which may be transferred upon bodily contact. Rabies ispresent in most desert mammal populations. Do not take anycontracting fleas or rabies from any animal by adopting pets.

Rats are carriers of various parasites and gastrointestinal diseasespresence in unsanitary locations.

chances of

due to their

Section Il. Environmental Effects on Personnel

There is no reason to fear the desert environment, and it should not adverselyaffect the morale of a soldier/marine who is prepared for it. Lack of naturalconcealment has been known to induce temporary agoraphobia (fear of openspaces) in some troops new to desert conditions, but this fear normallydisappears with acclimatization. Remember that there is nothing unique abouteither living or fighting in deserts; native tribesmen have lived in the Sahara forthousands of years. The British maintained a field army and won a campaign inthe Western Desert in World War II at the far end of a 12,000-mile sea line ofcommunication with equipment considerably inferior to that in service now. Thedesert is neutral, and affects both sides equally; the side whose personnel are bestprepared for desert operations has a distinct advantage.

The desert is fatiguing, both physically and mentally. A high standard ofdiscipline is essential, as a single individuals lapse may cause serious damage tohis unit or to himself. Commanders must exercise a high level of leadership andtrain their subordinate leaders to assume greater responsibilities required by thewide dispersion of units common in desert warfare. Soldiers/marines with goodleaders are more apt to accept heavy physical exertion and uncomfortable

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conditions. Every soldier/marine must clearly understand why he is fighting insuch harsh conditions and should be kept informed of the operational situation.Ultimately, however, the maintenance of discipline will depend on individualtraining.

Commanders must pay special attention to the welfare of troops operating in thedesert, as troops are unable to find any comforts except those provided by thecommand. Welfare is an essential factor in the maintenance of morale in a harshenvironment, especially to the inexperienced. There is more to welfare than theprovision of mail and clean clothing. Troops must be kept healthy andphysically fit; they must have adequate, palatable, regular food, and be allowedperiods of rest and sleep. These things will not always be possible anddiscomfort is inevitable, but if troops know that their commanders are doingeverything they can to make life tolerable, they will more readily accept theextremes brought on by the environment.

HEAT

The extreme heat of the desert can cause heat exhaustion and heatstroke and putstroops at risk of degraded performance. For optimum mental and physicalperformance, body temperatures must be maintained within narrow limits. Thus,it is important that the body lose the heat it gains during work. The amount ofheat accumulation in the human body depends upon the amount of physicalactivity, level of hydration, and the state of personal heat acclimatization. Unitleaders must monitor their troops carefully for signs of heat distress and adjustschedules, work rates, rest, and water consumption according to conditions.

Normally, several physical and physiological mechanisms (e.g., convection andevaporation) assure transfer of excess body heat to the air. But when airtemperature is above skin temperature (around 92 degrees Fahrenheit) the

evaporation of sweat is the only operative mechanism. Following the loss ofsweat, water must be consumed to replace the bodys lost fluids. If the bodyfluid lost through sweating is not replaced, dehydration will follow. This willhamper heat dissipation and can lead to heat illness. When humidity is high,evaporation of sweat is inhibited and there is a greater risk of dehydration or heatstress. Consider the following to help prevent dehydration:

Heat, wind, and dry air combine to produce a higher individual waterrequirement, primarily through loss of body water as sweat. Sweat ratescan be high even when the skin looks and feels dry.

Dehydration nullifies the benefits of heat acclimatization and physicalfitness, it increases the susceptibility to heat injury, reduces the capacityto work, and decreases appetite and alertness. A lack of alertness can

indicate early stages of dehydration. Thirst is not an adequate indicator of dehydration. The soldier/marine

will not sense when he is dehydrated and will fail to replace body waterlosses, even when drinking water is available. The universal experiencein the desert is that troops exhibit voluntary dehydration that is, theymaintain their hydration status at about 2 percent of body weight (1.5quarts) below their ideal hydration status without any sense of thirst.

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Chronic dehydration increases the incidence of several medical problems:constipation (already an issue in any field situation), piles (hemorrhoids), kidneystones, and urinary infections. The likelihood of these problems occurring canbe reduced by enforcing mandatory drinking schedules.

Resting on hot sand will increase heat stress--the more a body surface is incontact with the sand, the greater the heat stress. Ground or sand in full sun ishot, usually 30-45 degrees hotter than the air, and may reach 150 degreesFahrenheit when the air temperature is 120 degrees Fahrenheit. Cooler sand is

just inches below the surface; a shaded trench will provide a cool resting spot.

At the first evidence of heat illness, have the troops stop work, get into shade,and rehydrate. Early intervention is important. Soldiers/ marines who are nottaken care of can become more serious casualties.

ACCLIMATIZATIONAcclimatization to heat is necessary to permit the body to reach and maintainefficiency in its cooling process. A period of approximately 2 weeks should beallowed for acclimatization, with progressive increases in heat exposure andphysical exertion. Significant acclimatization can be attained in 4-5 days, butfull acclimatization takes 7-14 days, with 2-3 hours per day of exercise in theheat. Gradually increase physical activity until full acclimatization is achieved.

Acclimatization does not reduce, and may increase, water requirements.Although this strengthens heat resistance, there is no such thing as totalprotection against the debilitating effects of heat. Situations may arise where it is

not possible for men to become fully acclimatized before being required to doheavy labor. When this happens heavy activity should be limited to cooler hoursand troops should be allowed to rest frequently. Check the weather daily.Day-to-day and region-to-region variations in temperatures, wind, and humiditycan be substantial.

CLIMATIC STRESS

Climatic stress on the human body in hot deserts can be caused by anycombination of air temperature, humidity, air movement, and radiant heat. Thebody is also adversely affected by such factors as lack of acclimatization, beingoverweight, dehydration, alcohol consumption, lack of sleep, old age, and poor

health.

The body maintains its optimum temperature of 98.6 degrees Fahrenheit byconduction/convection, radiation, and evaporation (sweat). The most importantof these in the daytime desert is evaporation, as air temperature alone is probablyalready above skin temperature. If, however, relative humidity is high, air willnot easily evaporate sweat and the cooling effect is reduced. The following

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paragraphs describe the effects of radiant light, wind, and sand on personnel indesert areas.

Radiant LightRadiant light comes from all directions. The suns rays, either direct or reflectedoff the ground, affect the skin and can also produce eyestrain and temporarilyimpaired vision. Not only does glare damage the eyes but it is very tiring;therefore, dark glasses or goggles should be worn.

Overexposure to the sun can cause sunburn. Persons with fair skin, freckledskin, ruddy complexions, or red hair are more susceptible to sunburn than others,but all personnel are susceptible to some degree. Personnel with darkercomplexions can also sunburn. This is difficult to monitor due to skinpigmentation, so leaders must be ever vigilant to watch for possible sunburnvictims. Sunburn is characterized by painful reddened skin, and can result in

blistering and lead to other forms of heat illness.Soldier/marines should acquire a suntan in gradual stages (preferably in theearly morning or late afternoon) to gain some protection against sunburn. Theyshould not be permitted to expose bare skin to the sun for longer than fiveminutes on the first day, increasing exposure gradually at the rate of five minutesper day. They should be fully clothed in loose garments in all operationalsituations. This will also reduce sweat loss. It is important to remember that

The sun is as dangerous on cloudy days as it is on sunny days.

Sunburn ointment is not designed to give complete protection againstexcessive exposure.

Sunbathing or dozing in the desert sun can be fatal.

Wind

The wind can be as physically demanding as the heat, burning the face, arms, andany exposed skin with blown sand. Sand gets into eyes, nose, mouth, throat,lungs, ears, and hair, and reaches every part of the body. Even speaking andlistening can be difficult. Continual exposure to blown sand is exhausting anddemoralizing. Technical work spaces that are protected from dust and sand arelikely to be very hot. Work/rest cycles and enforced water consumption will berequired.

The combination of wind and dust or sand can cause extreme irritation to mucousmembranes, chap the lips and other exposed skin surfaces, and can causenosebleed. Cracked, chapped lips make eating difficult and causecommunication problems. Irritative conjunctivitis, caused when fine particlesenter the eyes, is a frequent complaint of vehicle crews, even those wearinggoggles. Lip balm and skin and eye ointments must be used by all personnel.Constant wind noise is tiresome and increases soldier/marine fatigue, thusaffecting alertness.

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When visibility is reduced by sandstorms to the extent that military operationsare impossible, soldiers/marines should not be allowed to leave their group forany purpose unless secured by lines for recovery.

The following are special considerations when performing operations in dust orsand:

Contact lenses are very difficult to maintain in the dry dusty environmentof the desert and should not be worn except by military personneloperating in air conditioned environments, under command guidance.

Mucous membranes can be protected by breathing through a wet facecloth, snuffing small amounts of water into nostrils (native water is notsafe for this purpose) or coating the nostrils with a small amount ofpetroleum jelly. Lips should be protected by lip balm.

Moving vehicles create their own sandstorms and troops traveling in openvehicles should be protected.

Scarves and bandannas can be used to protect the head and face.

The face should be washed as often as possible. The eyelids should becleaned daily.

BASIC HEAT INJURY PREVENTION

The temperature of the body is regulated within very narrow limits. Too littlesalt causes heat cramps; too little salt and insufficient water causes heatexhaustion. Heat exhaustion will cause a general collapse of the bodys coolingmechanism. This condition is heatstroke, and is potentially fatal. To avoid these

illnesses, troops should maintain their physical fitness by eating adequately,drinking sufficient water, and consuming adequate salt. If soldiers/marinesexpend more calories than they take in, they will be more prone to heat illnesses.Since troops may lose their desire for food in hot climates, they must beencouraged to eat, with the heavier meal of the day scheduled during the coolerhours.

It is necessary to recognize heat stress symptoms quickly. When suffering fromheatstroke, the most dangerous condition, there is a tendency for a soldier/marineto creep away from his comrades and attempt to hide in a shady and secludedspot; if not found and treated, he will die. When shade is required during theday, it can best be provided by tarpaulins or camouflage nets, preferably doubled

to allow air circulation between layers and dampened with any surplus water.

Approximately 75 percent of the human body is fluid. All chemical activities inthe body occur in a water solution, which assists in the removal of toxic bodywastes and plays a vital part in the maintenance of an even body temperature. Aloss of 2 quarts of body fluid (2.5 percent of body weight) decreases efficiencyby 25 percent and a loss of fluid equal to 15 percent of body weight is usually

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fatal. The following are some considerations when operating in a desertenvironment:

Consider water a tactical weapon. Reduce heat injury by forcing waterconsumption. Soldiers/marines in armored vehicles, MOPP gear, and in

body armor need to increase their water intake. When possible, drink Cool (50-55 degrees Fahrenheit) water.

Drink one quart of water in the morning, at each meal, and beforestrenuous work. In hot climates drink at least one quart of water eachhour. At higher temperatures hourly water requirements increase to overtwo quarts.

Take frequent drinks since they are more often effective than drinking thesame amount all at once. Larger soldiers/marines need more water.

Replace salt loss through eating meals.

When possible, work loads and/or duration of physical activity should beless during the first days of exposure to heat, and then should gradually

be increased to follow acclimatization.

Modify activities when conditions that increase the risk of heat injury(fatigue/loss of sleep, previous heat exhaustion, taking medication) arepresent.

Take frequent rest periods in the shade, if possible. Lower the work rateand work loads as the heat condition increases.

Perform heavy work in the cooler hours of the day such as early morningor late evening, if possible.

A description of the symptoms and treatment for heat illnesses follows:

Heat cramps.

Symptoms: Muscle cramps of arms, legs, and/or stomach. Heavysweating (wet skin) and extreme thirst.

First aid: Move soldier/marine to a shady area and loosen clothing.Slowly give large amounts of cool water. Watch the soldier/marineand continue to give him water, if he accepts it. Get medical help ifcramps continue.

Heat exhaustion.

- Symptoms: Heavy sweating with pale, moist, cool skin; headache,weakness, dizziness, and/or loss of appetite; heat cramps, nausea(with or without vomiting), rapid breathing, confusion, and tingling

of the hands and/or feet. First aid: Move the soldier/marine to a cool, shady area and

loosen/remove clothing. Pour water on the soldier/marine and fanhim to increase the cooling effect. Have the soldier/ marine slowlydrink at least one full canteen of water. Elevate the soldiers/marineslegs. Get medical help if symptoms continue; watch thesoldier/marine until the symptoms are gone or medical aid arrives.

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Heatstroke.

Symptoms: Sweating stops (red, flushed, hot dry skin).

First aid: Evacuate to a medical facility immediately. Move the

soldier/marine to a cool, shady area and loosen or remove clothing ifthe situation permits. Start cooling him immediately. Immerse himin water and fan him. Massage his extremities and skin and elevatehis legs. If conscious, have the soldier/marine slowly drink one fullcanteen of water.

WATER SUPPLY

Maintaining safe, clean, water supplies is critical. The best containers for smallquantities of water (5 gallons) are plastic water cans or coolers. Water in plasticcans will be good for up to 72 hours; storage in metal containers is safe only for24 hours. Water trailers, if kept cool, will keep water fresh up to five days. If the

air temperature exceeds 100 degrees Fahrenheit, the water temperature must bemonitored. When the temperature exceeds 92 degrees Fahrenheit, the watershould be changed, as bacteria will multiply. If the water is not changed thewater can become a source of sickness, such as diarrhea. Ice in containers keepswater cool. If ice is put in water trailers, the ice must be removed prior to movingthe trailer to prevent damage to the inner lining of the trailer.

Potable drinking water is the single most important need in the desert. Ensurenonpotable water is never mistaken for drinking water. Water that is not fit todrink but is not otherwise dangerous (it may be merely oversalinated) may beused to aid cooling. It can be used to wet clothing, for example, so the body doesnot use too much of its internal store of water.

Use only government-issued water containers for drinking water. Carry enoughwater on a vehicle to last the crew until the next planned resupply. It is wise toprovide a small reserve. Carry water containers in positions that

Prevent vibration by clamping them firmly to the vehicle body.

Are in the shade and benefit from an air draft.

Are protected from puncture by shell splinters.

Are easily dismounted in case of vehicle evacuation,

Troops must be trained not to waste water. Water that has been used for washingsocks, for example, is perfectly adequate for a vehicle cooling system.

Obtain drinking water only from approved sources to avoid disease or water thatmay have been deliberately polluted. Be careful to guard against pollution ofwater sources. If rationing is in effect, water should be issued under the closesupervision of officers and noncommissioned officers.

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Humans cannot perform to maximum efficiency on a decreased water intake. Anacclimatized soldier/marine will need as much (if not more) water as thenonacclimatized soldier/marine, as he sweats more readily. If the ration water isnot sufficient, there is no alternative but to reduce physical activity or restrict itto the cooler parts of the day.

In very hot conditions it is better to drink smaller quantities of water often ratherthan large quantities occasionally. Drinking large quantities causes excessivesweating and may induce heat cramps. Use of alcohol lessens resistance to heatdue to its dehydrating effect. As activities increase or conditions become moresevere, increase water intake accordingly.

The optimum water drinking temperature is between 10 degrees Celsius and 15.5degrees Celsius (50-60 degrees Fahrenheit). Use lister bags or even wet clotharound metal containers to help cool water.

Units performing heavy activities on a sustained basis, such as a forced march ordigging in, at 80 degrees wet bulb globe temperature index, may require morethan 3 gallons of drinking water per man. Any increase in the heat stress willincrease this need. In high temperatures, the average soldier/marine will require9 quarts of water per day to survive, but 5 gallons are re commended. Details onwater consumption and planning factors are contained in Appendix G.

While working in high desert temperatures, a man at rest may lose as much as apint of water per hour from sweating. In very high temperatures and lowhumidity, sweating is not noticeable as it evaporates so fast the skin will appeardry. Whenever possible, sweat should be retained on the skin to improve thecooling process; however, the only way to do this is to avoid direct sun on the

skin. This is the most important reason why desert troops must remain fullyclothed. If a soldier/marine is working, his water loss through sweating (andsubsequent requirement for replenishment) increases in proportion to the amountof work done (movement). Troops will not always drink their required amount ofliquid readily and will need to be encouraged or ordered to drink more than theythink is necessary as the sensation of thirst is not felt until there is a body deficitof 1 to 2 quarts of water. This is particularly true during the period ofacclimatization. Packets of artificial fruit flavoring encourages consumption dueto the variety of pleasant tastes.

All unit leaders must understand the critical importance of maintaining theproper hydration status. Almost any contingency of military operations will act

to interfere with the maintenance of hydration. Urine provides the best indicatorof proper hydration. The following are considerations for proper hydrationduring desert operations:

Water is the key to your health and survival. Drink before you becomethirsty and drink often, When you become thirsty you will be about aquart and a half low.

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Carry as much water as possible when away from approved sources ofdrinking water. Man can live longer without food than without water.

Drink before you work; carry water in your belly, do not save it in yourcanteen. Learn to drink a quart or more of water at one time and drink

frequently to replace sweat losses.Ensure troops have at least one canteen of water in reserve, and knowwhere and when water resupply will be available.

Carbohydrate/electrolyte beverages (e.g., Gatorade) are not required, andif used, should not be the only source of water. They are tooconcentrated to be used alone. Many athletes prefer to dilute these 1:1with water. Gaseous drinks, sodas, beer, and milk are not goodsubstitutes for water because of their dehydrating effects.

If urine is more colored than diluted lemonade, or the last urinationcannot be remembered, there is probably insufficient water intake.Collect urine samples in field expedient containers and spot check the

color as a guide to ensuring proper hydration. Very dark urine warns ofdehydration. Soldiers/marines should observe their own urine, and usethe buddy system to watch for signs of dehydration in others.

Diseases, especially diarrheal diseases, will complicate and often preventmaintenance of proper hydration.

Salt, in correct proportions, is vital to the human body; however, the more a mansweats, the more salt he loses. The issue ration has enough salt for asoldier/marine drinking up to 4 quarts of water per day. Unacclimatized troopsneed additional salt during their first few days of exposure and allsoldiers/marines need additional salt when sweating heavily. If the waterdemand to balance sweat loss rises, extra salt must be taken under medical

direction. Salt, in excess of body requirements, may cause increased thirst and afeeling of sickness, and can be dangerous. Water must be tested before addingsalt as some sources are already saline, especially those close to the sea.

COLD

The desert can becombine to produce

dangerously cold. The dry air, wind, and clear sky canbone-chilling discomfort and even injury. The ability of the

body to maintain body temperature within a narrow range is as important in thecold as in the heat. Loss of body heat to the environment can lead to cold injury;a general lowering of the body temperature can result in hypothermia, and localfreezing of body tissues can lead to frostbite. Hypothermia is the major threat

from the cold in the desert, but frostbite also occurs.

Troops must have enough clothing and shelter to keep warm. Remember, woodis difficult to find; any that is available is probably already in use. Troops maybetempted to leave clothing and equipment behind that seems unnecessary (andburdensome) during the heat of the day. Cold-wet injuries (immersion foot ortrench foot) may be a problem for dismounted troops operating in the coastal

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marshes of the Persian Gulf during the winter. Some guidelines to follow whenoperating in the cold are-

Anticipate an increased risk of cold-wet injuries if a proposed operationincludes lowland or marshes. Prolonged exposure of the feet in cold

water causes immersion foot injury, which is completely disabling.

Check the weatherknow what conditions you will be confronting. Thedaytime temperature is no guide to the nighttime temperature;90-degree-Fahrenheit days can turn into 30-degree-Fahrenheit nights.

The effects of the wind on the perception of cold is well known.Windchill charts contained in FM 21-10 allow estimation of thecombined cooling power of air temperature and wind speed compared tothe effects of an equally cooling still-air temperature.

CLOTHING

Uniforms should be worn to protect against sunlight and wind. Wear theuniform loosely. Use hats, goggles, and sunscreen. Standard lightweightclothing is suitable for desert operations but should be camouflaged in desertcolors, not green. Wear nonstarched long-sleeved shirts, and full-length trouserstucked into combat boots. Wear a scarf or triangular bandanna loosely aroundthe neck (as a sweat rag) to protect the face and neck during sandstorms againstthe sand and the sun. In extremely hot and dry conditions a wet sweat rag wornloosely around the neck will assist in body cooling.

Combat boots wear out quickly in desert terrain, especially if the terrain is rocky.The leather drys out and cracks unless a nongreasy mixture such as saddle soapis applied. Covering the ventilation holes on jungle boots with glue or epoxiesprevents excessive sand from entering the boots. Although difficult to do, keepclothing relatively clean by washing in any surplus water that is available. Whenwater is not available, air and sun clothing to help kill bacteria.

Change socks when they become wet. Prolonged wear of wet socks can lead tofoot injury. Although dry desert air promotes evaporation of water from exposedclothing and may actually promote cooling, sweat tends to accumulate in boots.

Soldier/marines may tend to stay in thin clothing until too late in the desert dayand become susceptible to chills--so respiratory infections may be common.Personnel should gradually add layers of clothing at night (such as sweaters), andgradually remove them in the morning. Where the danger of cold weather injuryexists in the desert, commanders must guard against attempts by inexperiencedtroops to discard cold weather clothing during the heat of the day.

Compared to the desert battle dress uniform (DBDU) the relative impermeabilityof the battle dress overgarment (BDO) reduces evaporative cooling capacity.Wearing underwear and the complete DBDU, with sleeves rolled down and

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under the chemical protective garment, provides additional protection againstchemical poisoning. However, this also increases the likelihood of heat stresscasualties.

HYGIENE AND SANITATION

Personal hygiene is absolutely critical to sustaining physical fitness. Take everyopportunity to wash. Poor personal hygiene and lack of attention to siting oflatrines cause more casualties than actual combat. Field Marshal Rommel lostover 28,400 soldiers of his Afrika Corps to disease in 1942. During the desertcampaigns of 1942, for every one combat injury, there were three hospitalizedfor disease. Hygiene and sanitation are covered in detail in FM 21-10. Thissection highlights some of the points that are of special importance to thecommander in the desert.

Proper standards of personal hygiene must be maintained not only as a deterrentto disease but as a reinforcement to discipline and morale. If water is available,shave and bathe daily. Cleaning the areas of the body that sweat heavily isespecially important; change underwear and socks frequently, and use footpowder often. Units deployed in remote desert areas must have a means ofcutting hair therefore, barber kits should be maintained and inventoried prior toany deployment. If sufficient water is not available, troops should cleanthemselves with sponge baths, solution-impregnated pads, a damp rag, or even adry, clean cloth. Ensure that waste water is disposed of in an approved area toprevent insect infestation. If sufficient water is not available for washing, a fieldexpedient alternative is powder baths, that is, using talcum or baby powder to drybathe.

Check troops for any sign of injury, no matter how slight, as dirt or insects cancause infection in minor cuts and scratches. Small quantities of disinfectant inwashing water reduces the chance of infection. Minor sickness can have seriouseffects in the desert. Prickly heat for example, upsets the sweating mechanismand diarrhea increases water loss, making the soldier/marine more prone to heatillnesses. The buddy system helps to ensure that prompt attention is given tothese problems before they incapacitate individuals.

Intestinal diseases can easily increase in the desert. Proper mess sanitation isessential. Site latrines well away and downwind of troop areas and lagers.

Trench-type latrines should be used where the soil is suitable but must be dugdeeply, as shallow latrines become exposed in areas of shifting sand. Funnelsdug into a sump work well as urinals. Layer the bottom of slit trenches with limeand cover the top prior to being filled in. Ensure lime is available after each useof the latrine. Flies area perpetual source of irritation and carry infections. Onlygood sanitation can keep the fly problem to a minimum. Avoid all local tribecamps since they are frequently a source of disease and vermin.

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DESERT SICKNESS

Diseases common to the desert include plague, typhus, malaria, dengue fever,dysentery, cholera, and typhoid. Diseases which adversely impact hydration,

such as those which include nausea, vomiting, and diarrhea among theirsymptoms, can act to dramatically increase the risk of heat (and cold) illness orinjury. Infectious diseases can result in a fever; this may make it difficult todiagnose heat illness. Occurrences of heat illness in troops suffering from otherdiseases complicate recovery from both ailments.

Many native desert animals and plants are hazardous. In addition to injuries as aresult of bites, these natural inhabitants of the desert can be a source of infectiousdiseases.

Many desert plants and shrubs have a toxic resin that can cause blisters, or spinesthat can cause infection. Consider milky sap, all red beans, and smoke from

burning oleander shrubs, poisonous. Poisonous snakes, scorpions, and spidersare common in all deserts. Coastal waters of the Persian Gulf contain hazardousmarine animals including sea snakes, poisonous jellyfish, and sea urchins.

Skin diseases can result from polluted water so untreated water should not beused for washing clothes; although it can be used for vehicle cooling systems orvehicle decontamination.

The excessive sweating common in hot climates brings on prickly heat and someforms of fungus infections of the skin. The higher the humidity, the greater thepossibility of their occurrence. Although many deserts are not humid, there areexceptions, and these ailments are common to humid conditions.

The following are additional health-related considerations when operating in adesert environment:

The most common and significant diseases in deserts include diarrhealand insectborne febrile (i.e., fever causing) illnesses-both types of thesediseases are preventable.

Most diarrheal diseases result from ingestion of water or foodcontaminated with feces. Flies, mosquitoes, and other insects carryfever-causing illnesses such as malaria, sand fly fever, dengue (fever withsevere pain in the joints), typhus, and tick fevers.

There are no safe natural water sources in the desert. Standing water isusually infectious or too brackish to be safe for consumption. Units andtroops must always know where and how to get safe drinking water.

Avoid brackish water (i.e., salty). It, like sea water, increases thirst; italso dehydrates the soldier/marine faster than were no water consumed.Brackish water is common even in public water supplies, Iodine tabletsonly kill germs, they do not reduce brackishness.

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Water supplies with insufficient chlorine residuals, native food and drink,and ice from all sources are common sources of infective organisms.

PREVENTIVE MEASURESBoth diarrheal and insectborne diseases can be prevented through a strategywhich breaks the chain of transmission from infected sources to susceptiblesoldiers/marines by effectively applying the preventive measures contained inFM 21-10. Additional preventive measures are described below:

Careful storage, handling and purification/preparation of water and foodare the keys to prevention of diarrheal disease. Procure all food, water,ice, and beverages from US military approved sources and inspect themroutinely.

Well-cooked foods that are steaming hot when eaten are generally safe,as are peeled fruits and vegetables.

Local dairy products and raw leafy vegetables are generally unsafe.

Consider the food in native markets hazardous. Avoid local food unlessapproved by medical personnel officials.

Assume raw ice and native water to be contaminated--raw ice cannot beproperly disinfected. Ice has been a major source of illness in all priorconflicts; therefore, use ice only from approved sources.

If any uncertainty exists concerning the quality of drinking water, troopsshould disinfect their supplies using approved field-expedient methods(e.g., hypochlorite for lister bags, iodine tablets for canteens, boiling).

Untreated water used for washing or bathing risks infection.

Hand washing facilities should be established at both latrines and messfacilities. Particular attention should be given to the cleanliness of handsand fingernails. Dirty hands are the primary means of transmittingdisease.

Dispose of human waste and garbage as specified in FM 21-10.Additional considerations regarding human waste and garbage are--

Sanitary disposal is important in preventing the spread of diseasefrom insects, animals, and infected individuals, to healthysoldiers/marines.

Construction and maintenance of sanitary latrines are essential.

Burning is the best solution for waste. Trench latrines can be used if the ground is suitable, but they must be

dug deeply enough so that they are not exposed to shifting sand, andthey must have protection against flies and other insects that can usethem as breeding places.

Food and garbage attract animals--do not sleep where you eat andkeep refuse areas away from living areas.

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Survey the unit area for potential animal hazards.

Shakeout boots, clothing, and bedding before using them.

Section III. Environmental Effects onEquipment

Conditions in an arid environment can damage military equipment and facilities.Temperatures and dryness are major causes of equipment failure, and windaction lifts and spreads sand and dust, clogging and jamming anything that hasmoving parts. Vehicles, aircraft, sensors, and weapons are all affected. Rubbercomponents such as gaskets and seals become brittle, and oil leaks are morefrequent. Ten characteristics of the desert environment may adversely affectequipment used in the desert:

Terrain.

Heat.

Winds.

Dust and sand.

Humidity.

Temperature variations.

Thermal bending.

Optical path bending.

Static electricity.

Radiant light.

The relative importance of each characteristic varies from desert to desert.Humidity, for example, can be discounted in most deserts but is important in thePersian Gulf.

TERRAIN

Terrain varies from nearly flat, with high trafficability, to lava beds and saltmarshes with little or no trafficability. Drivers must be well trained in judgingterrain over which they are driving so they can select the best method ofovercoming the varying conditions they will encounter. Techniques for drivingand operating equipment in desert conditions are contained in Appendix C.

Track vehicles are well suited for desert operations. Wheel vehicles may beacceptable as they can go many places that track vehicles can go; however, theirlower speed average in poor terrain maybe unacceptable during some operations.Vehicles should be equipped with extra fan belts, tires, (and other items apt to

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malfunction), tow ropes (if not equipped with a winch), extra water cans, anddesert camouflage nets. Air-recognition panels, signal mirrors, and a tarpaulin forcrew sun protection are very useful. Wheel vehicles should also carry mats, orchannels as appropriate, to assist in freeing mired vehicles.

The harsh environment requires a very high standard of maintenance, which mayhave to be performed well away from specialized support personnel. Operatorsmust be fully trained in operating and maintaining their equipment. Some typesof terrain can have a severe effect on suspension and transmission systems,especially those of wheel vehicles. Tanks are prone to throw tracks whentraveling over rocks.

Track components require special care in the desert. Grit, heat, and bad tracktension accelerate track failure. Sprockets wear out quickly in sandy conditions.Track pins break more easily in high temperatures and high temperatures alsoincrease rubber/metal separation on road wheels. Proper track tension is critical,as loose track is easily thrown and excessive tension causes undue stress on track

components.

Increase the unit PLL of tires and tracks as sand temperatures of 165 degreesFahrenheit are extremely detrimental to rubber, and weaken resistance to sharprocks and plant spines, Items affected by mileage such as wheels, steering, trackwedge bolts and sprocket nuts, and transmission shafts, must be checked forundue wear when conducting before-, during-, and after-operations maintenance.

HEAT

Vehicle coding and lubrication systems are interdependent. A malfunction byone will rapidly place the other system under severe strain. In temperatureextremes, all types of engines are apt to operate above optimum temperatures,leading to excessive wear, or leaking oil seals in the power packs, and ultimately,engine failure. Commanders should be aware which types of vehicles are proneto excessive overheating, and ensure extra care is applied to their maintenance.The following are considerations for ensuring engines do not overheat:

Check oil levels frequently to ensure proper levels are maintained (toohigh may be as bad as too low), that seals are not leaking, and oilconsumption is not higher than normal.

Keep radiators and air flow areas around engines clean and free of debrisand other obstructions.

Fit water-cooled engines with condensers to avoid steam escapingthrough the overflow pipe.

Cooling hoses must be kept tight (a drip a second loses 7 gallons of fluidin 24 hours).

Operators should not remove hood side panels from engine compartmentswhile the engine is running as this causes air turbulence and leads toineffective cooling.

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Batteries do not hold their charge efficiently in intense heat. Check them twicedaily. The following are additional considerations for maintaining batteries inintense heat:

Change battery specific gravity to adjust to the desert environment (seevehicle TMs for details).

Keep batteries full, but not overfilled, and carry a reserve of distilledwater.

Keep air vents clean, or vapors may build up pressure and cause thebattery to explode.

Set voltage regulators as low as practical.

Increase dry battery supplies to offset high attrition rate caused by heatexposure.

Severe heat increases pressure in closed pressurized systems such as the M2 fire

burner unit, and increases the volume of liquids. Ensure that the workingpressure of all equipment is within safety limits and be careful when removingitems such as filler caps.

Treat Halon fire extinguishers with care. High temperatures may cause them todischarge spontaneously. Put wet rags on them during the hottest part of the dayto keep them coder.

Some items of equipment are fitted with thermal cutouts that open circuitbreakers whenever equipment begins to overheat. Overheating is often causedby high ambient temperatures, and can be partly avoided by keeping the item inthe shade or wrapping it in a wet cloth to maintain a lower temperature by

evaporation.

Flying time and performance of helicopters are degraded as the altitude and heatincreases. Helicopter performance is also affected by humidity. Aircraftcanopies have been known to bubble under direct heat and should be coveredwhen not in use.

Ammunition must be out of direct heat and sunlight. Use camouflage nets andtarpaulins to provide cover. Ammunition cool enough to be held by bare hands issafe to fire.

Wood shrinks in a high-temperature, low-humidity environment. Equipment,

such as axes carried on track vehicles, can become safety hazards as heads arelikely to fly off shrunken handles.

Radiators require special attention. Proper cooling-system operation is critical inhigh-temperature environments. Check cooling systems for serviceability priorto deployment. Local water maybe high in mineral content which will calcify incooling systems. Distilled water is better since tap water contains chemicals that

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will form a crusty coating inside the radiator and will ultimately clog it. Amixture of 40 percent antifreeze and 60 percent water is usuallyacceptable--check your appropriate technical manual to be certain.

During movement, and at operation sites where extremely hot temperatures exist,continuous protection from the heat is necessary for medical items and supplies,which deteriorate rapidly.

Air and all fluids expand and contract according to temperature. If tires areinflated to correct pressure during the cool of night, they may burst during theheat of day. If fuel tanks are filled to the brim at night, they will overflow atmidday. Servicing these items during the heat of day can result in low tirepressure, overheating of tires, and a lack of endurance if the fuel tanks were notfilled to their correct levels. Air pressure in tires must be checked when theequipment is operating at efficient working temperatures, and fuel tanks must befilled to their correct capacity as defined in the appropriate technical manual.

These items should be checked several times a day and again at night.

The major problem with radios in a desert environment is overheating. Thefollowing steps can help prevent overheating of radios:

Keep radios out of direct sunlight.

Place a piece of wood on top of the radio. Leaving space between thewood and the top of the radio will help cool the equipment. Operating onlow power whenever possible will also help.

Place wet rags on top of radios to help keep them cool and operational.Do not cover the vents.

Any oil or fuel blown onto a cooler (heat exchanger) will gather and quicklydegrade cooling. Fix even slight leaks promptly. Do not remove cooling ductsor shrouds. Check them for complete coverage--use tape to seal cracks. Do notremove serviceable thermostats if overheating occurs.

WINDS

Desert winds, by their velocity alone, can be very destructive to large andrelatively light materiel such as aircraft, tentage, and antenna systems. Tominimize the possibility of wind damage, materiel should be sited to benefit from

wind protection and should be firmly picketed to the ground.

DUST AND SAND

Dust and sand are probably the greatest danger to the efficient functioning ofequipment in the desert. It is almost impossible to avoid particles settling onmoving parts and acting as an abrasive. Sand mixed with oil forms an abrasivepaste.

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Lubricants must be of the correct viscosity for the temperature and kept to therecommended absolute minimum in the case of exposed or semiexposed movingparts. Lubrication fittings are critical items and should be checked frequently.If they are missing, sand will enter the housing causing bearing failure. Teflonbearings require constant inspection to ensure that the coating is not being

eroded.

Proper lubrication is crucial for success. Wipe off all grease fittings before youattach the grease gun and after use. Keep cans of grease covered to prevent sandcontamination. Preserve opened grease containers by covering and sealing withplastic bags. Use of grease cartridges in lieu of bulk grease is preferred. AllPOL dispensing tools must be stored in protected areas to prevent contamination.Place a tarpaulin, or other material, under equipment being repaired to preventtools and components from being lost in the sand. The automotive-artillerygrease pos

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Desert Ops