Mountain Living

Convection
2-73. Convection is the loss of heat due to moving air or water in contact with the skin. Wind chill is
convection cooling. Clothing that ventilates, insulates, and protects must control the layer of warm air next
to the skin.

Evaporation
2-74. The evaporation of perspiration causes heat loss. Wet clothing can cause heat loss by conduction and
evaporation. Dressing in layers allows Soldiers to remove or add clothing as needed.

COMMON COLD-WEATHER INJURIES
2-75. Some of the most common cold-weather injuries are described in the following paragraphs:

Shock
2-76. Shock is the depressed state of vital organs due to the cardiovascular (heart) system not providing
enough blood. Although shock is not a cold-weather injury, it is a symptom or a result of other injuries.
Any illness or injury can produce shock, which increases the instance and severity of a cold-weather injury.
Shock should be assumed in all injuries and treated accordingly. Even minor injuries can produce shock
due to cold, pain, fear, and loss of blood.
Symptoms
2-77. Initial symptoms of shock include apprehension, shortness of breath, sweating, cold skin, rapid and
faint pulse, and excessive thirst. If the victim is not given adequate first aid immediately, his condition may
digress into incoherence, slower heart beat, unconsciousness, and possibly death.
Treatment
2-78. To treat shock, restore breathing and heart rate through artificial respiration or cardiopulmonary
resuscitation. Treat the injury and control hemorrhaging. Make the victim as comfortable as possible and
try to relieve the pain. Keep the victim warm but do not overheat him. Elevate the back and head, or feet. If
the victim is conscious and has no abdominal injuries, administer water. The victim should receive proper
medical attention as soon as possible.

Dehydration
2-79. Dehydration is the loss of body fluids to the point that normal body functions are prevented or
slowed. This is usually caused by overexertion and improper water intake. Dehydration precedes all
cold-weather injuries and is a major symptom in acute mountain sickness. It contributes to poor
performance in all physical activities―even more so than lack of food. Cold weather requirements for
water are no different than in the desert. They may, in fact, exceed desert requirements because of the
increased difficulty in moving with extra clothing and through the snow. At high altitudes, the air is dry.
Combined with a rapid rate of breathing, as much as two liters of liquid may be lost each day through
respiration. A Soldier needs about three to six quarts of water each day to prevent dehydration when living
and performing physical labor in a cold or mountainous environment. Coffee and tea are diuretics and
cause excessive urination and should be avoided. The adequacy of liquid intake can best be judged by the
urine color and volume. Dark amber colored urine instead of light yellow or the absence of a need to
urinate upon awakening from a night’s sleep are indicators of dehydration. Thirst is not a good indicator of
hydration.
Contributing Factors
2-80. Factors that contribute to dehydration in cold weather are—

The thirst mechanism does not function properly in cold weather.

Water is often inconvenient to obtain and purify.

26 July 2012

TC 3-97.61

2-15