Chad Kahler, Michael Staudenmaier Jr., Mark Loeffelbein and the National Weather Service HeatRisk Development Team

Heat is the leading weather-related cause of death in the U.S., claiming more lives annually than any other hazard. Yet until recently, few tools existed to offer individuals information they could use on hot days to gauge the health risk in their specific location.

To make heat warnings more effective, a National Weather Service team led by Michael Staudenmaier, Chad Kahler and Mark Loeffelbein devised the first high-resolution, gridded heat-alert system that provides a seven-day, localized forecast of the possible heat risk.

“This system enhances National Weather Service efforts to safeguard lives and property, particularly for those most vulnerable to heat and the communities that support them,” said Stephen Bieda III, the NWS chief of the Severe, Fire, Public, and Winter Weather Services Branch.

Bieda said HeatRisk helps decision-makers in various sectors, including emergency management, public health and education take proactive measures during heat events, including opening cooling centers and staffing hospitals on hot days. Operators of parks, schools and outdoor venues can also use the data to decide if it is safe to hold outdoor activities. And heat-sensitive individuals can protect themselves before heat reaches extreme levels.

The innovative approach uses a color-coded numeric system that is easy for the public to understand. By combining climatology data with Centers for Disease Control and Prevention mortality data, HeatRisk can predict the risk of heat-related effects over a 24-hour period.

In the summer of 2024, the system became an important part of news and weather channel programming.

“Integration of health data with weather forecasts is something that has not been tried before,” Bieda said.

Now, people can plug in their zip code for localized heat forecasts and safety recommendations and more precisely figure out when temperatures could pose a risk to their health, he added.

Michelle Mainelli, NWS deputy director, said, “We tried to make this as accessible to the general public as possible, so that vulnerable communities can [get the information] they need to make some of those decisions.”

The tool has been used after disasters, particularly in communities without power or air conditioning.

Each team member played a vital role in making the system a reality. Staudenmaier provided the initial vision and leadership for developing the HeatRisk tool, managing resources and his team’s expertise to achieve success. He also was instrumental in expanding the tool nationally and collaborating with CDC to incorporate health data.

Kahler provided valuable insights on the technical challenges of expanding the tool nationally, particularly around computational requirements. Loeffelbein was essential for software development and distribution, working under tight timelines and overcoming technical hurdles.

“Fundamentally, it’s pretty amazing to know that we have put together something that is saving lives and property across the country on a daily basis in the summer,” Staudenmaier said.