Cold-Weather Operations:
Preparation

1. Units preparing for deployment to cold-weather regions must anticipate the effects of the environment on the functioning of the individual as well as the unit. Preparation should involve steps to minimize those effects.

   a. When assessing weather conditions for troops operating in mountainous regions or for flight personnel in aircraft, altitude may need to be considered, if weather measurements are obtained from stations at low elevations. Temperatures, windchills, and the risk of cold injury at high altitudes can differ considerably from those at low elevations.

   1. In general, it can be assumed that air temperature is 3.6°F lower with every 1000 feet above the site at which temperature was measured.
      
      
   2. Winds are usually more severe at high altitude, and there is less cover above the tree line.
      
      
   3. Individuals are more susceptible to frostbite and other cold injuries at altitudes above 8,000 feet than at sea level, due to the lower temperatures, higher winds, and lack of oxygen.

   
   

   b. Shelter from weather is critical. The standard shelter is the tent, but improvised shelters (snow caves, snow trenches, lean-tos, etc.) can be constructed from local materials.

   c. The US Army has several heaters for use inside tents during cold weather. The type of heater required depends on the size of the tent or shelter to be heated. Usually, the Yukon stove is used to heat the Arctic 10 Man Squad Tent, 5 man tents and GP small tents. The Squad stove M1950 is used in improvised shelters or small tents housing 2 to 5 men. Larger capacity stoves are available for the bigger tents. All these stoves provide heat and can be used to melt ice and snow or to heat water.

   d. The recommended sleeping system is the Extreme Cold-Weather Sleeping Bag (NSN 8465-01-033-8057), on top of a polyfoam sleeping mat (NSN 8465-01-109-3367).

   
   

2. Units deploying to cold-weather regions should conduct training for their Soldiers on basic winter skills and cold-weather survival.

   a. Humans do not acclimatize to cold weather nearly as well as they can acclimatize to hot weather, although repeated cold exposure does produce what is referred to as habituation. Proper training before deploying into cold-weather regions is more important for prevention of cold injuries than repeatedly being exposed to cold temperatures.

   1. Following habituation, shivering is much less vigorous. This is advantageous because shivering is inefficient, and most of the heat produced is lost. Also, shivering can interfere with sleep, causing fatigue.
      
      
   2. With habituation to repeated cold exposure, humans adjust mentally and emotionally. Training outdoors in cold weather before deployment will help build confidence in Soldiers' ability to physically, mentally, and emotionally contend with the stress of cold-weather conditions.

   
   

   
   

   b. Soldiers should practice performing their duties while wearing cold-weather clothing, since this gear restricts movement considerably. It is also important that Soldiers practice donning individual nbc.htm protective gear while wearing cold-weather clothing.

   c. Soldiers wearing rubberized or tight-fitting boots are at risk for trenchfoot regardless of weather conditions, since sweat accumulates inside these boots and keeps the feet wet.

   d. Feet, hands, and exposed skin must be kept dry. Feet are particularly vulnerable, and extra foot care is required for cold-weather operations. Feet should be washed, dried, and dusted with a dry, antifungal powder (NSN 6505-01-008-3054) daily. Socks must be changed whenever they become wet from exposure to rain or snow, or from excess sweat. This may require changing into dry socks at least 2-3 times daily.

   e. Susceptibility to cold injuries can be minimized by maintaining proper hydration and nutrition, avoiding alcohol, caffeine, and nicotine, and minimizing periods of inactivity in cold conditions. Minimize the risk of cold injuries in fighting positions, sentry points, and observation points by placing pads, sleeping bags, tree boughs, etc inside these positions to allow occupants to insulate themselves from the ground or snow. High levels of physical fitness are also beneficial for Soldiers participating in cold-weather operations.

   f. Leaders should provide warm water frequently to encourage personal hygiene. Soldiers should wash hands, feet, face, and groin daily, whether or not heated water is available. During training exercises lasting several weeks, commanders should consider whether the health (and morale) benefits of arranging for troops to leave the field briefly for a break at a heated shower site might outweigh the cost of temporarily suspending a realistic training scenario.

   
   

3. Winter operations are physically demanding, and troops must be in peak physical condition.

   a. Units on alert, or identified for future deployment, should immediately optimize their physical training program, and spend more time training outdoors in the cold to accustom themselves to the effects of cold.

   b. Outdoor training should not be halted when temperatures are cold. Rather than restrict outdoor activities at certain preselected temperatures, commanders should establish programs in which increasingly protective countermeasures (clothing, surveillance) are initiated as conditions become colder. Such programs build Soldiers' confidence in their ability to complete their missions, regardless of weather.

   c. Persons 45 years old or older may be less cold tolerant than younger persons, due to the decline in physical fitness that often occurs with aging. This emphasizes the importance of physical fitness training, particularly for older Soldiers.

4. Each Soldier must have an individual cold-weather survival kit and all required cold-weather clothing in proper working condition.

   a. Cold-weather clothing systems are designed to change with the wearer's needs. Cold-weather clothing protection is based on the principles of insulation, layering, and ventilation. By understanding these principles, Soldiers can vary their clothing to regulate protection and stay comfortable.

   1. Insulation depends on the clothing thickness, properties of the garment material, and the amount of air trapped within the garment. When clothing is dirty, the material tends to be packed down, which compromises insulation.
      
      
   2. Wearing clothing ensembles in multiple layers allows the wearer to remove or add clothes to adjust the insulation to changes in environment or workload as well as to the individual's own needs and preferences. Wearing layered clothing is especially important for Soldiers whose duties require them to frequently move in and out of heated shelters, or to periodically undertake vigorous physical activity.
      
      
   3. Physically active people can sweat even in extremely cold weather. Sweat will be able to evaporate if clothing allows ventilation. Proper clothing will be made of material that water vapor can pass through, and will allow the wearer to unzip and open the clothing periodically to increase ventilation. If sweat cannot evaporate, it will accumulate and wet the clothing, compromising insulation. Sweat evaporation will be compromised when clothing is dirty.

   
   

   
   

   b. The US Army has two different clothing systems in the inventory for issue to troops operating in cold-weather conditions: a Cold/Wet-Cold/Dry Clothing System (FM 31-70), and an Extended Cold-Weather Clothing System (FM 21-15).

   1. Soldiers deployed to cold-weather areas from stations in warm regions are usually issued the combination Cold/Wet-Cold/Dry Clothing System, which can be configured into two ensembles. The cold/wet ensemble is worn above 14°F, and the cold/dry ensemble is worn below 14°F. The cold/dry ensemble protects down to -60°F. The cold/wet configuration differs from the cold/dry in the number of layers and the choice of boots. The system uses layers of wool/cotton fabrics to trap air for insulation, and a water-repellent outer garment to maintain dryness.
      
      
   2. Soldiers regularly stationed in cold-weather regions are usually issued the Extended Cold-Weather Clothing System (ECWCS) which protects from +40°F to -60°F. ECWCS consists of 5 layers: polypropylene underwear, a polyester fiberpile shirt and bib overalls, polyester coat liner and nylon/cotton field pants, nylon/GORE-TEX® laminate parka and trousers, and white nylon/cotton overgarments (parka and trousers). The inner layers are made of fabrics which draw perspiration away from the skin. The outer layer is made of a material which repels outside water while allowing perspiration to be evaporated. Either the cold-weather vapor barrier boot (Type I) or the extreme cold-weather vapor barrier boot (Type II) can be worn with one pair of nylon/cotton/wool socks (OG-106). The Combat Vehicle Crewman's Hood (Balaclava) is worn under the PASGT helmet. The polypropylene layer and the nylon/GORE-TEX® Parka and trousers should always be worn to prevent perspiration from building up inside the clothes. Wool or wool blends should not be worn in the intermediate layers of the ECWCS because they retain moisture.

   
   

   
   

   c. Several varieties of handwear protection are available for issue.

   1. Most Soldiers receive the standard light-duty leather glove which is worn with a 50% wool, 50% nylon liner inserted. This handwear ensemble provides inactive persons with about 30 minutes of protection from frostbite when air temperature is 0°F. If temperatures are warmer and/or Soldiers are physically active, the handwear ensemble will provide effective protection for longer periods. The light-duty leather glove is not waterproof.
      
      
   2. When the standard light-duty leather glove provides inadequate protection, (i.e. air temperature below 0°F, or more than 30 minutes of inactive exposure is anticipated) trigger finger or Extreme Cold Weather mittens and liners can be worn.

   
   
   
5. In addition to conducting training to help Soldiers prepare to operate and survive under cold-weather conditions, unit leaders should anticipate how the disruption of normal unit procedures due to the weather conditions will affect unit operations.

   a. Identify unit members who have previously experienced cold injuries. These Soldiers should receive intensive retraining in cold-injury prevention, and should be monitored closely while deployed.

   b. Establish a buddy system within the unit to increase unit cohesiveness by minimizing the sense of isolation that individuals may experience during cold weather. A buddy system will also help to monitor for signs of cold injury among unit members.

   c. Field sanitation procedures should be reviewed and modified as necessary if weather conditions are extreme. Aspects requiring particular re-emphasis include placement, maintenance, and closure of latrines, water purification, and sanitary food handling.

   d. Anticipate supply difficulties, and stockpile emergency stores of critical items. During cold-weather operations, units will need more of the larger sizes of NBC protective clothing, since Soldiers wear NBC clothing over multiple layers of bulky cold-weather clothing. Develop storage and transportation procedures for food and water which prevent freezing, and determine measures for thawing frozen supplies. Set up procedures for keeping rations hot until received by individual Soldiers in the field.

   e. Establish safety SOPs for personnel travelling by vehicle away from the unit's bivouac site. At a minimum, these SOPs should require all vehicle occupants to have their sleeping bag, extra clothing, and individual survival kit with them whenever they leave the unit area. The SOPs should also designate what actions are to be taken in case the vehicle is disabled or the driver becomes lost.

   f. Snowshoes or skis should be used for dismounted troop movement when loose snow is deeper than 15 inches. Although easier than walking through deep snow, snowshoeing and skiing are hard work and troops require proper equipment and training to use these techniques.

   g. Building defenses in hard frozen ground may require engineer support in the form of heavy equipment for digging and plowing.

   h. Keep liquid medications and medical equipment from freezing.

   i. Extra clothing and blankets should be available for use by patients during treatment and evacuation, especially when their clothing has become torn or soaked in blood.

   j. Maintain larger stocks of large sizes of food serving gloves for food handlers to wear over glove liners when they are serving food outdoors.

   k. Chlorine or iodine purification of cold water requires twice the usual amount of chemical and an extra 15 minutes waiting period before the water is safe to drink. Flavor enhancers should be added just before consuming the water.

   l. Clothing and equipment malfunctions occur more often during cold weather. The properties of materials used to make the clothing and equipment are altered by low temperatures. Rubber, plastic, other manmade fabric and materials and even metal can become brittle and break more easily when cold. Zippers will freeze and break rendering garments unusable.