MOUNTAINOUS AREAS

8-11. Characteristics of mountain ranges include rugged, poorly trafficable terrain, steep slopes, and altitudes greater than 1,600 feet. Irregular mountain terrain provides numerous places for cover and concealment. Because of rocky ground, it is difficult and often impossible to dig belowground positions; therefore, boulders and loose rocks are used in aboveground construction. Irregular fields of fire and dead spaces are considered when designing and locating fighting positions in mountainous areas. FM 3-97.6 and FM 3-97.61 provide additional information on fighting positions and camouflage and concealment in mountainous areas.

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8-12. Reverse-slope positions are rarely used in mountainous terrain but they do have special applications; crest and near-crest positions on high ground are much more common. Direct-fire weapon positions in mountainous areas are usually poorly concealed by large fields of fire. Indirect-fire weapon positions are better protected from both direct and indirect fire when located behind steep slopes and ridges.

Special Environments 8-13. Another important design consideration in mountain terrain is the requirement for substantial overhead cover. The adverse effects of artillery bursts above a protective position are greatly enhanced by rock and gravel displacement or avalanche. Construction materials used for both structural and shielding components are most often indigenous rocks, boulders, and rocky soil. Often, rock formations are used as structural wall components without modification. Conventional tools are inadequate for preparing individual and crew-served weapons fighting positions in rocky terrain. Engineers assist with light equipment and tools (such as pneumatic jackhammers) delivered to mountain areas by helicopter. Explosives and demolitions can be used for positions requiring rock and boulder removal.

8-14. In areas with rocky soil or gravel, wire cages or gabions are used as building blocks in protective walls, structural walls, and fighting positions. Gabions are constructed of lumber, plywood, wire fence, or any suitable material that forms a stackable container for soil or gravel. The two-person mountain shelter is basically a hole 7 feet long, 3 ½ feet wide, and 3 ½ feet deep. The hole is covered with 6- to 8-inch diameter logs with evergreen branches, a shelter half, or local material such as topsoil, leaves, snow, and twigs placed on top. The floor is usually covered with evergreen twigs, a shelter half, or other expedient material. Entrances can be provided at both ends or a fire pit is sometimes dug at one end for a small fire or stove. A low earth berm is built around the position to provide more height for the occupants.

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8-15. The color of mountainous terrain varies across the spectrum of color, depending on the minerals in the soil, whether tree or other vegetation covered, and the time of the day. No color or combination of colors matches all mountainous terrain.

Topography

8-16. Mountainous terrain is extremely varied to include plateaus that may include similarities to desert terrain. The likelihood that selected portions will also be snow covered is also high.

Shadows

8-17. The closer a target is to the ground, the smaller its shadow; and a small shadow is easier to conceal from aerial observation. The proper draping of camouflage nets will alter or disrupt the regular, sharp-edged shadows of military targets and allow target shadows to appear more like natural shadows. When supplemented by artificial materials, natural shadows cast by folds of the ground can be used for camouflage and concealment purposes. The best solution to the shadow problem in mountainous terrain is to blend in with the natural shadows and use overhead concealment or cover for terrain masking. Remember that shadows may shift dramatically during the daylight hours. Park vehicles in a way that minimizes their broadside exposure to the sun.

Placement

8-18. Proper placement and shadow disruption remain effective techniques. Place assets in gullies, folds, ravines, overhangs, and other natural cover and concealment to reduce their shadows and silhouettes and to take advantage of terrain masking. Less dispersion is typically necessary than in desert terrain or other relatively flat areas. Move assets as the sun changes position to keep equipment in shadows.

Terrain Mottling

8-19. The scarring techniques associated with terrain mottling may work in selected situations but is less likely to be useful than perhaps in desert areas. (See paragraph 6-66 for information about terrain mottling.)

Movement Discipline

8-20. Movement discipline is especially important in mountainous terrain. The irregular surfaces will make movement less fluid, potentially loosening stone and other materials that will fall to lower levels producing an audible and visual signature. Dust and diesel plumes may also be highlighted against the backdrop

Chapter 8

8-4 ATP 3-37.34/MCWP 3-17.6 Publication Date

terrain. Shine or reflection may also be an issue since it can be seen for an extended distance. Shade optical devices (binoculars, gun sights) when using them.

Noise and Light Discipline

8-21. Noise and light discipline is particularly important in mountainous terrain, since sound and light can be detected at greater distance and sounds caused by falling objects may last for a longer time. The techniques for reducing these signatures remain the same as for other environments. Starting all vehicle and equipment engines simultaneously is a technique that can be used to confuse enemy acoustical surveillance efforts.

DESERTS

8-22. Deserts are extensive, arid, and treeless; suffer from a severe lack of rainfall; and possess extreme daily temperature fluctuations. The terrain is sandy with boulder-strewn areas, mountains, dunes, deeply-eroded valleys, areas of rock and shale, and salt marshes. Effective natural barriers are found in steep slope rock formations. Wadis and other dried up drainage features are used extensively for protective position placement. FM 90-3/MCWP 3-35.6 provides additional information on fighting positions and camouflage and concealment in deserts.

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8-23. Designers of fighting and protective positions in desert areas must consider the lack of available natural cover and concealment. The only minimal cover available is through the use of terrain masking; therefore, positions are often completed above ground. Mountain and plateau deserts have rocky soil or “surface chalk” soil which makes digging difficult. In these areas, rocks and boulders are used for cover. Most often, berms used in desert fighting or protective positions are undesirable because of probable enemy detection in the flat desert terrain. Deep-cut positions are also difficult to construct in soft sandy areas because of wall instability during excavations. Revetments are almost always required, unless excavations are very wide and have gently sloping sides of 45 degrees or less. Designing overhead cover is additionally important because nuclear explosions have increased fallout due to easily displaced sandy soil.

8-24. Indigenous materials are usually used in desert position construction. However, prefabricated structures and revetments for excavations, if available, are ideal. Although excavation may be relatively easy, depending on the soil type, additional care must be taken to prevent sandy soil from caving into fighting positions and survivability construction must include adequate surface area and compaction of the bearing surface for posts and beams. In addition, the open terrain, persistent winds, and the type of soil may require frequent maintenance of earth berms to correct wind and water erosion issues. Metal culvert revetments are quickly emplaced in easily excavated sand. Sandbags, sand-filled ammunition boxes, and soil-filled containers are also used for containing backsliding soil. Therefore, camouflage and concealment, as well as light and noise discipline, are important considerations during position construction. Target acquisition and observation are relatively easy in desert terrain.

CAUTION

Unless it is constructed properly, any fighting position can easily collapse and crush or bury the Soldiers/Marines within. The instability of sand soils makes positions constructed in such soil especially prone to this hazard. It is critical that positions are built according to established guidelines outlined in this ATP, FM 5-34/MCRP 3-17A, and GTA 05-08-001.

Special Environments

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8-25. The color of desert terrain varies from pink to blue, depending on the minerals in the soil and the time of the day. No color or combination of colors matches all deserts. Patches of uniform color in the desert are usually ten times larger than those in wooded areas. These conditions have led to the development of a neutral, monotone tan as the best desert camouflage paint color.

Topography

8-26. Although desert terrain may appear featureless, it is not completely flat. In some ways, desert terrain resembles unplowed fields; barren, rocky areas; grasslands; and steppes.

Shadows

8-27. The closer a target is to the ground, the smaller its shadow; and a small shadow is easier to conceal from aerial observation. The proper draping of camouflage nets will alter or disrupt the regular, sharp-edged shadows of military targets and allow target shadows to appear more like natural shadows. When supplemented by artificial materials, natural shadows cast by folds of the ground can be used for camouflage and concealment purposes. The best solution to the shadow problem in desert terrain is to dig in and use overhead concealment or cover. Otherwise, park vehicles in a way that minimizes their broadside exposure to the sun.

Placement

8-28. Proper placement and shadow disruption remain effective techniques. Place assets in gullies, washes, wadis, and ravines to reduce their shadows and silhouettes and to take advantage of terrain masking. More dispersion is necessary in desert terrain than in wooded areas. Move assets as the sun changes position to keep equipment in shadows.

Terrain Mottling

8-29. Use terrain mottling when the ground offers little opportunity for concealment. (See paragraph 6-66 for information about terrain mottling.)