![]() ![]() Scientists are not sure why this occurs, but they think it is a signal to close down blood vessels in the skin and extremities so more blood can flow to the body’s core, to keep your organs warm and keep you alive-even if you lose a finger or toe to frostbite in the process. Your nerve endings and brain perceive the rapid drop in skin temperature as extreme, however. Once the wind surpasses 25 mph or so, it whisks away heat more quickly than your body can emit it, leaving your skin exposed to the full low temperature. Wind carries some of that heat away, however, and the faster the wind, the faster the heat loss. If you stand still in air that is 20 degrees F and there is no wind, your skin will be warmer than 20 degrees F. Thanks to blood in your skin and underlying tissue, your body constantly radiates heat, generating a thin boundary layer of warm air on the surface your skin that helps insulate you from the cold. So what’s the point of wind chill, then? Should we worry about it? Is it deceiving? Wind chill is a mathematically derived number that approximates how cold your skin feels-not how cold your skin actually is. The coldest your uncovered face could get would be 15 degrees F whether the wind is calm or howling at 40 mph. Your skin temperature cannot drop below the actual air temperature. But if the air temperature is, say, 15 degrees F, and a 20–mile per hour wind makes the wind chill –2 degrees F, would the temperature of your exposed skin drop to that temperature? No. Alarmed weather forecasters are now routinely displaying big maps that show the extremely low wind chill values: –34 degrees Fahrenheit in Minneapolis, –36 degrees F in Chicago, –39 degrees F in Fargo, N.D., last night alone. and Canada in a deep freeze several times already this winter. The infamous polar vortex has put the U.S. By purchasing a subscription you are helping to ensure the future of impactful stories about the discoveries and ideas shaping our world today. If you're enjoying this article, consider supporting our award-winning journalism by subscribing. ![]()
0 Comments
Leave a Reply. |