An extreme weather event in which there is a prolonged period of above-normal temperatures. “Prolonged” means anything from a few days to a few weeks; “above normal” means above the expected averages for that place at that season. Heat waves may be accompanied by other climatic events, for instance episodes of severe smog in large urban regions, and the combination of heat and smog is dangerous to health for infants, the elderly, and persons with chronic cardiovascular or respiratory disease. Severe heat waves can cause heavy mortality even in otherwise favorable living conditions. For instance, a heat wave in western Europe in 2003 killed an estimated 25,000, mostly infirm elderly people or frail infants. The climate models of global warming scenarios suggest that heat waves will increase in frequency and severity in coming decades.
Subjects: Public Health and Epidemiology.