Chapter 1

BIVOUAC SITE
1-113. Bivouac sites must be protected from rockfall, wind, lightning, avalanche run-out zones, and
flooding (especially in gullies). If the possibility of falling exists, rope in, the tent and all equipment may
have to be tied down.

EQUIPMENT
1-114. Ropes are not total security; they can be cut on a sharp edge or break due to poor maintenance,
age, or excessive use. You should always pack emergency and bivouac equipment even if the weather
situation, tour, or a short climb is seemingly low of dangers.

OBJECTIVE HAZARDS
1-115. Objective hazards are caused by the mountain and weather and cannot be influenced by man, for
example, storms, rockfalls, icefalls, and lightning.

ALTITUDE
1-116. At high altitudes, especially over 6,500 feet, endurance and concentration is reduced. Cut down on
smoking and alcohol. Sleep well, acclimatize slowly, stay hydrated, and be aware of signs and symptoms of
high-altitude illnesses. Storms can form quickly and lightning can be severe.

VISIBILITY
1-117. Fog, rain, darkness, and or blowing snow can lead to disorientation. Take note of your exact
position and plan your route to safety before visibility decreases. Cold combined with fog can cause a thin
sheet of ice to form on rocks (verglas). Whiteout conditions can be extremely dangerous. If you must move
under these conditions, it is best to rope up. Have the point man move to the end of the rope. The second
man will use the first man as an aiming point with the compass. Use a route sketch and march table. If the
tactical situation does not require it, plan route so as not to get caught by darkness.

GULLIES
1-118. Rock, snow, and debris are channeled down gullies. If ice is in the gully, climbing at night may be
better because the warming of the sun will loosen stones and cause rockfalls.

ROCKFALL
1-119. Blocks and scree at the base of a climb can indicate recurring rockfall. Light colored spots on the
wall may indicate impact chips of falling rock. Spring melt or warming by the sun of the rock/ice/snow
causes rockfall.

AVALANCHES
1-120. Avalanches are caused by the weight of the snow overloading the slope. (Refer to paragraph 1-125
for more detailed information on avalanches.)

HANGING GLACIERS AND SERACS
1-121. Avoid, if at all possible, hanging glaciers and seracs. They will fall without warning regardless of
the time of day or time of year. One cubic meter of glacier ice weighs 910 kilograms (about 2,000 pounds).
If you must cross these danger areas, do so quickly and keep an interval between each person.

CREVASSES
1-122. Crevasses are formed when a glacier flows over a slope and makes a bend, or when a glacier
separates from the rock walls that enclose it. A slope of only two to three degrees is enough to form a

1-24

TC 3-97.61

26 July 2012