Wind Chill - A New Way to Tell How Cold is Cold

Page 16

     For over a year, there have been discussions between the National Weather Service and the Meteorological Services of Canada about updating the Wind Chill Temperature Index. During the Fall of 2000, a special group - consisting of the National Weather Service, the Meteorological Services of Canada and the International Society of Biometeorology - evaluated the existing wind chill formula and made changes to improve it. The group's goal was to internationally upgrade and standardize the Wind Chill Temperature Index.
     The new Wind Chill Temperature Index makes use of advances in meteorology, biometeorology and computer modeling to provide a more accurate, useful formula for calculating the dangers from winter winds and freezing temperatures. In addition, clinical trials were conducted and the results of those trials has been used to verify and improve the accuracy of the new formula.
     The Wind Chill Temperature Index will be implemented in Canada and the United States, resulting in a consistent index for North America. This implementation will involve the entire meteorological community and the

media -- which will play an important role in explaining the index to the general public. In this way, an accurate and consistent measure will be provided to help the public protect itself against the dangers of frostbite and hypothermia.

Specifically, the new Wind Chill Temperature Index:

• uses calculated wind speed at an average height of five feet (typical height of a human face) based on readings from the national standard height of 33 feet (typical height of an anemometer);
  
• is based on the latest heat transfer theory, i.e., heat loss from the body to its surroundings, during cold and breezy/windy days;
  
• uses a standard factor for skin tissue and assumes a no sunlight scenario.
  

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