COLD WEATHER ISSUES
| Wind-Chill Chart Frost Bite Dehydration Hypothermia |
Cold Weather Injuries Trench Foot Immersion Foot |
| WET COLD | > 14 F average 24h Freeze at night then thaw during day--ground slushy--wet snow/rain |
| DRY COLD | < 14 F average 24h Ground frozen--dry snow--no thaw |
Summary of conditions:
Wet Cold.
Wet-cold conditions occur where variations in day and night temperatures cause alternate freezing and thawing. These conditions are often accompanied by wet snow and rain causing the ground to become slushy and muddy. Wet cold requires clothing with a waterproof or water-repellent, wind- resistant outer layer, and an insulated inner layer sufficient for moderately cold weather of 14°F and above. Waterproof footwear is essential.Dry Cold.
Dry-cold conditions occur when average temperatures are lower than 14° F. The ground is usually frozen and the snow dry. These low temperatures and wind increase the need to protect the entire body. Dry cold requires layered clothing that insulates against a wind-chill. The inner layers of insulation must be protected by a water-repellent, wind-resistant outer layer.
Intense Cold.
Intense cold air temperatures ( -5 to -25°
F) are in the range where materials begin to change, adversely affecting operations. Fuels gel, back blast areas triple, artillery fires drop 100 per 1000 meters, water in containers freezes quickly. Appropriate protective clothing is required.Extreme Cold.
Extreme cold (below -25° F) inhibits full-scale combat. Special fuels and lubricants are required, rubber becomes stiff and brittle, and close tolerances are affected. Operator personnel must have special protection from the elements.
SURVIVAL
Water, Food, Shelter
Protective clothing
* Will to survive* --Training/equipment
Head 60-80% of body heat
| C
O L D |
Clean
clothing Overheating Loose, layered clothes Dry clothing |
(Insulation)
(sweat=perspiration) (air insulation layers on/off) (mittens/socks on rucksack unfolded, near body near top of shelter inside sleeping bag shell keep sleeping bag dry) |
Overheating can cause perspiration which can lead to hypothermia in cold weather situations.
|
NON FREEZING: |
Hypothermia
Dehydration Trench foot Immersion Foot |
FREEZING: |
Frostbite |
FACTORS THAT INFLUENCE COLD WEATHER INJURIES (CWI)
| Previous
CWI Race Geological Origin Ambient Temperature Wind Chill Factor Type of Mission Terrain Nutrition Alcohol, Drugs, Tobacco |
Clothing
Moisture Dehydration Age Fatigue Other Injury Discipline Activity Sharp Changes in Weather |
PREVENTION OF COLD WEATHER INJURIES
| Training Planning Weather Data Foot Care Proper Use of Gloves/Headgear Proper Undergarments |
HYPOTHERMIA
Hypothermia is when your body’s heat loss exceeds the rate that your body can produce it. Your body can produce only a limited amount of heat to keep yourself warm. When your body is producing as much heat as it can and your body temperature is still lowering, you are suffering from hypothermia. Hypothermia can occur no matter what the temperature is.
It is important to know the symptoms and treatment for hypothermia.
| CAUSES: Heat loss exceeds heat production | |
| Wind/water
chill Radiation--heat like light Conduction--sitting on cold surface--handling cold objects Convection--wind/water Evaporation--wet clothing Respiration--breathing cold air |
|
| Symptoms: | ||
| Intense shivering Feeling of deep/cold numbness Muscle tensing Fatigue Poor coordination Disorientation |
Blueness
of skin Slow, weak, irregular pulse Slurred speech Retreat inward psychologically Dullness Apathy |
|
| Treatment: | |
| Immediately
raise body temperature Shelter from wind and weather Insulate from ground Replace wet clothing with dry Increase exercise if possible Give hot drinks and food Get in warm sleeping bag Shared body warmth Hot packs/hand warmers under armpits and groin area |
|
DEHYDRATION
Cause: Not consuming as much water as the body uses
| Symptoms of normal dehydration: | |
| Higher
temperature Poor skin tugor Upset stomach Dizziness |
Weakness
Confusion Dryness of mouth and throat Difficulty swallowing |
Symptoms of SEVERE dehydration: Similar to hypothermia
|
Typical hypothermia/dehydration differentiation test: |
Warm
belly--dehydration Cold belly-- hypothermia |
Cold weather dehydration can lead to total body core cooling.
| Cause: | Exposure to wet and cold around freezing |
| Symptoms: | Feet and toes are pale and numb, cold, and stiff |
| NOTE: | If preventive action not taken at this stage feet will swell and become painful! |
| Treatment: | Do NOT rub or massage |
|
Clean carefully with soap
and water if indoors |
| Cause: | Prolonged immersion in cold water < 50 F or in wet footwear > 12 hours. Aching and stinging pain on prolonged exposure. Initially no unusual |
| Symptoms: | Sensations of pain. Shin becomes shriveled and soft. |
| NOTE: | Handle gently--same as trench foot. |
Cause: Freezing of skin or tissues due to exposure to temperatures at or below freezing.
Commonly by exposure to liquids that freeze at low temperatures such as gasoline, cleaning solvents, and salt water, or high velocity wind flow or metal surfaces.
EXPOSURE CAN OCCUR IN MINUTES!
Wind or contact with wet clothing may produce an effective temp in freezing range when air temperature is above freezing.
| SYMPTOMS: | First degree: | Aching, tingling sensation with cold and numbness. Skin usually turns red. |
| Second degree: | Pale grey and waxy white. | |
| Third degree: | Black--no feeling no blood flow |
|
TREATMENT: |
Handle gently--same as trench foot. DO NOT use water to warm affected areas. |
| CHEEKS: | Cover with warm hands until pain returns |
| FINGERS: | Place uncovered under arm pits or belly next to skin. |
| FEET: | Bare feet against belly of companion, under clothing avoid rubbing or massaging. Don’t pop blisters! |
| CLOTHING: | DRY, and proper for weather. |
| EXERCISE: | Routine exercise of face, fingers, and toes. |