In 2001, the National Weather Service, in cooperation with other
research institutions and the Canadian Meteorological Centre, a new method of
calculating the Wind Chill was implemented. This replaces the former method
which had been used for over 55 years.
The new method uses the wind speed calculated at an average
height of 5 feet above ground, about the face level of most people, rather then
the previous standard of 33 feet above ground. This new more accurate method
of calculating wind chill is more understandable and more accurate, and has
been verified with clinical trials. In 2002, adjustments for solar radiation
and sky cover (cloudy, sunny) will be added to the model.
New Wind Chill Index Formula:
Wind Chill (°F) = 35.74 + 0.6215T
- 35.75 (V^0.16)
+ 0.4275T (V^0.16) where T is the air temperature (°F) and V is
the wind velocity (mph)
Medical Risks and Dangers of Prolonged
Exposure to Cold Temperatures
Frostbite is damage to body tissue caused by
that tissue being frozen. Frostbite causes a loss of feeling and a white or
pale appearance in the extremities, such as fingers, toes, ear lobes or the
tip of the nose. If symptoms are detected, get medical help immediately! If
you must wait for help, slowly rewarm affected areas. However, if the person
is also showing signs of hypothermia, warm the body core before the extremities.
Frostbite will occur within 15 minutes when exposed to wind chill of 18 degrees
below zero or colder.
Hypothermia (low body temperature) Warning Signs: uncontrollable shivering, memory
losss, disorientation, incoherence, slurred speech, drowsiness and apparent
exhaustion. Detection: Take the person's temperature.
If below 95°F (35°C), immediately seek medical help!
If medical help is not available, begin warming the person slowly. Warm
the body core first. If needed, use your own body heat to help. Get the person
into dry clothing and wrap them in a warm blanket, covering the head and neck.
Do not give the person alcohol, drugs, coffee
or any hot beverage or food; warm broth is best.
Do not warm the extremities (arms and legs) first! This drives the cold blood
toward the heart and can lead to heart failure.
For more information on Cold and dangers of cold exposure, contact
your local medical resource.
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