f winter - not lightning, hurricanes, tornadoes, floods, or earthquakes - takes a greater toll. In the 40-year period from 1936 through 1975, nearly 20,000 people were killed in the United States by the effects of heat and solar radiation. In the disastrous heat wave of 1980, more than 1,250 people died. And these are the direct casualties. No one can know how many more deaths are advanced by heat wave weather - how many diseased or aging hearts surrender that under better conditions would have continued functioning. How does NOAA keep the public informed about heat waves? With the National Weather Service Heat Index Program, the National Weather Service (NWS) has stepped up its efforts to alert more effectively the general public and appropriate authorities to the hazards of heat waves - those prolonged excessive heat/humidity episodes. Based on the latest research findings, the NWS has devised the "Heat Index" (HI), (sometimes referred to as the "apparent temperature"). The HI, given in degrees F, is an accurate measure of how hot it really feels when relative humidity (RH) is added to the actual air temperature. IMPORTANT...Since HI values were devised for shady, light wind conditions, EXPOSURE TO FULL SUNSHINE CAN INCREASE HI VALUES BY UP TO 15 degrees F. Also, STRONG WINDS, PARTICULARLY WITH VERY HOT, DRY AIR, CAN BE EXTREMELY HAZARDOUS. Heat Index How does the NWS alert the public to the occurrence of a heat wave? The NWS will initiate alert procedures when the HI is expected to exceed 105 degrees to 110 degrees F (depending on local climate) for at least two consecutive days. The procedures are: Include HI values in zone and city forecasts. Issue Special Weather Statements and/or Public Information Statements presenting a detailed discussion of 1. the extent of the hazard including HI values, 2. who is most at risk, 3. safety rules for reducing the risk. Assist state/local health officials in preparing Civil Emergency Messa...
