In recent years, excessive heat has caused more deaths than all other weather events, including floods. A heat wave is a prolonged period of excessive heat, generally 10 degrees or more above average, often combined with excessive humidity.

You will likely hear weather forecasters use these terms when a heat wave is predicted in your community:

Excessive Heat Watch – Conditions are favorable for an excessive heat event to meet or exceed local Excessive Heat Warning criteria in the next 24 to 72 hours.

Heat Advisory – Heat Index values are forecasting to meet locally defined advisory criteria for 1 to 2 days (daytime highs= 100-105° Fahrenheit).

Excessive Heat Warning – Heat Index values are forecasting to meet or exceed locally defined warning criteria for at least 2 days (daytime highs= 105-110° Fahrenheit).

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