Heat Emergencies

Heat is the number one weather-related killer.  On average, more than 1,500 people in the U.S. die each year from excessive heat.  This number is greater than the 30-year mean annual number of deaths due to tornadoes, hurricanes, floods and lightning combined.  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.
North American summers are hot; most summers see heat waves in one section or another of the United States.   East of the Rockies, they tend to combine both high temperature and high humidity although some of the worst have been catastrophically dry.  Details on how heat impacts the human body is provided at "The Hazards of Excessive Heat".
Heat kills by pushing the human body beyond its limits.  In extreme heat and high humidity, evaporation is slowed and the body must work extra hard to maintain a normal temperature.
Most heat disorders occur because the victim has been overexposed to heat or has over-exercised for his or her age and physical condition.  Older adults, young children, and those who are sick or overweight are more likely to succumb to extreme heat.

Know the Terms. Familiarize yourself with these terms to help identify an extreme heat hazard:
Heat Wave. Prolonged period of excessive heat often combined with excessive humidity.
Heat Index. A number in degrees Fahrenheit (F) that tells how hot it feels when relative humidity is added to the air temperature. Exposure to full sunshine can increase the heat index by 15 degrees.
Heat Cramps. Muscular pains and spasms due to heavy exertion. Although heat cramps are the least severe, they are often the first signal that the body is having trouble with the heat.
Heat Exhaustion. Typically occurs when people exercise heavily or work in a hot, humid place where body fluids are lost through heavy sweating. Blood flow to the skin increases, causing blood flow to decrease to the vital organs. This results in a form of mild shock. If not treated, the victim’s condition will worsen. Body temperature will keep rising and the victim may suffer heat stroke.
Heat/Sun Stroke. A life-threatening condition. The victim’s temperature control system, which produces sweating to cool the body, stops working. The body temperature can rise so high that brain damage and death may result if the body is not cooled quickly.

Learn More about what to do Before and During extreme heat episodes.

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