What the Temperature Doesn’t Tell You About Extreme Heat’s Hazards
The new color-coded HeatRisk tool doesn't just convey how hot it is. It aims to provide information about the relative danger that weather poses.
A construction worker hydrates during a heat wave in Folsom, California, on July 3.
Photographer: David Paul Morris/BloombergAfter its nationwide rollout on Earth Day, the HeatRisk forecasting tool is getting a real-world test as deadly temperatures stress much of the US.
Created by the US Centers for Disease Control and Prevention and the National Oceanic and Atmospheric Administration, HeatRisk combines public health data and weather forecasts to create a map of threatening heat across the country. Similar to how tornadoes and hurricanes are categorized, the tool ranks heat waves on a scale of 0 to 4 based on how dangerous they are. This metric integrates local climatology — a 90F day in Seattle has more impact than in Las Vegas — the time of year, the forecast daily high and low temperature and the duration of heat.