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.

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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. 



WIND-CHILL CHART

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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)


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Overheating can cause perspiration which can lead to hypothermia in cold weather situations.


COLD WEATHER INJURIES  

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 doesn't matter if you are on vacation doing Breckenridge ski rentals or playing hockey on the local pond, location doesn't matter in cases of hypothermia either.
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.




TRENCH FOOT

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
Dry, elevate, and expose to room temperature
Stay off feet and replace socks





IMMERSION FOOT

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.

 




FROSTBITE

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.