Cold Weather Awareness
∙ During cold weather, the environment can directly affect an individual's health and performance. Cold can lower body temperature, resulting in cold injuries and impaired performance. Moreover, cold weather is often accompanied by wind, rain, snow and ice, which can worsen the effects of cold, as well as contribute to injury and performance.
∙ Operational problems often arise in cold weather, including restricted movement due to heavy clothing; equipment malfunctions; travel difficulties, etc.
∙ Humans protect themselves from cold primarily by avoiding or reducing cold exposure using clothing and shelter. When this protection proves inadequate, the body has biological defense mechanisms to help maintain correct body temperature. The body's internal mechanisms to defend its temperature during cold exposure include vasoconstriction and shivering. When these responses are triggered, it is a signal that clothing and shelter are inadequate.
∙ Vasoconstriction is the tightening of blood vessels in the skin when it is exposed to cold. The reduced skin blood flow conserves body heat, but, it can lead to discomfort, numbness, loss of dexterity in hands and fingers, and eventually cold injuries.
∙ Susceptibility to cold injuries can be minimized by maintaining proper hydration and nutrition, avoiding alcohol, caffeine and nicotine, minimizing periods of inactivity in cold conditions.
∙ 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.
∙ 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.
∙ With habituation to repeated cold exposure, humans adjust mentally and emotionally.
∙ Freezing cold injuries occur whenever air temperature is below freezing (32°F). Freezing limited to the skin surface is frost nip. When freezing extends deeper though the skin and flesh, the injury is frostbite.
∙ Frost nip - involves freezing of water on the skin surface - skin becomes reddened and possibly swollen; painful; usually no further damage after rewarming Frost nip should be taking seriously since it may be the first sign of impeding frostbite.
∙ Frostbite - Skin freezes at about 28°F. As frostbite develops, skin will become numb and turn to a gray or waxy-white color. The area will be cold to the touch and may feel stiff or woody. With frostbite, ice crystal formation and lack of blood flow to the frozen area damages the tissues. After thawing, swelling may occur, worsening the injury.
∙ First Aid for Frostbite
∙ Prevent further exposure
∙ Remove wet, constricting clothing
∙ Rewarm gradually by direct skin-to-skin contact between injured area and non injured skin of the victim or a buddy
∙ Evacuate for medical treatment (foot injuries by litter)
∙ Do not allow injury to refreeze during evacuation
∙ Hypothermia is a life threatening condition in which deep-body temperature falls below 95°F. Body temperature falls when the body cannot produce heat as fast as it is being lost.
∙ Hypothermia can occur rapidly during cold-water immersion (one hour or less when water temperature is below 45°F). Because water has a tremendous capacity to drain heat from the body, immersion in water considered even slightly cool, say 60°F, can cause hypothermia, if the immersion is prolonged for several hours.
∙ Hypothermia is a medical emergency. Hypothermia may be difficult to recognize in its early stages of development. Symptoms include unusually withdrawn or bizarre behavior, irritability, confusion, slowed or slurred speech, altered vision, uncoordinated movements and unconsciousness. Even mild hypothermia can cause victims to make poor decisions or act drunk (e.g., removing clothing when it is clearly inappropriate).
∙ Hypothermia victims may show no heartbeat, breathing or response to touch or pain when in fact they are not really dead.
∙ If hypothermia has resulted from submersion in cold water, cardiopulmonary resuscitation (CPR) should be initiated without delay. However, when hypothermia victims are found on land, it is important to take a little extra time searching for vital signs to determine whether CPR is really required.
∙ Hypothermia victims should be treated as gently as possible during treatment and evacuation, since the function of the heart can be seriously impaired in hypothermia victims. Rough handling can cause life-threatening disruptions in heart rate. All hypothermia victims, even those who do not appear to be alive, must be evaluated by trained medical personnel.
∙ Poorly conditioned persons are more susceptible to cold injury.
∙ Dehydration reduces skin blood flow. This increases susceptibility to cold injury.
∙ Persons 45 years old or older may be less cold tolerant than younger persons.
∙ Alcohol, and to a lesser extent caffeine, cause the blood vessels in the skin to open which may accelerate body heat loss.
∙ Nicotine decreases blood flow to the skin.
∙ Inadequate nutrition, illness and injury compromise the body's responses to cold.
∙ Being in places where movement is very restricted and individuals remain inactive for long periods of time will greatly increase the risk of cold injury.
∙ Individuals who have experienced a cold injury in the past are at greater risk of experiencing a cold injury than other individuals
∙ Activity: Too much or too little activity can contribute to cold injury. Over activity vs. Immobility.
∙ Wind increases heat loss from skin exposed to cold air.
PREVENTING COLD INJURY
· When Using Cold-Weather Clothing,
keep it -------- Clean
avoid ---------- Overheating
wear it -------- Loose in layers
keep it -------- Dry
· Wear or carry adequate clothing for the weather to be encountered.
· Wear clothing in loose layers to permit layers of air to provide good insulation and permit good circulation of blood to all parts of the body.
· Keep hands well protected.
· Avoid immobilization in the cold.
· Remove excess clothing when near a fire or in a warm enclosure.
MUST HAVE ITEMS FOR WINTER WEATHER DRIVING
· First aid kit
· A can of waterproof matches (to melt snow for water)
· Windshield scraper
· Booster cables
· Road map
· Tool kit
· Paper towels
· Bag of sand or course cat litter (for added traction)
· Tire chains (in areas with heavy snow) or snow tires
· Collapsible shovel
· High-calorie canned or dried food and a can opener
· Flashlight(s) and extra batteries
· Canned compressed air with sealant (for emergency tire repair)
· Brightly colored cloths
· A change of clean clothes, including socks.