All areas in the United States are at risk of drought at any time of the year. Drought gripped much of the West and Midwest from 1987 to 1991. The Missouri River Basin and California have experienced extended periods of drought as well. Temperatures that hover 10 degrees or more above the average high temperature for the region and last for several weeks are defined as extreme heat. Excessively dry and hot conditions can provoke dust storms and low visibility.
Droughts occur when a long period passes without substantial rainfall.
A heat wave combined with a drought is a very dangerous situation. In a normal year, approximately 175 Americans die from extreme heat. Young children, elderly people, and those who are sick or overweight are more likely to become victims. Between 1936 and 1975, nearly 20,000 people succumbed to the effects of heat and solar radiation. Because men sweat more than women, men are more susceptible to heat illness because they become more quickly dehydrated.