The National Weather Service and the Centers for Disease Control and Prevention have introduced a new color-coded heat warning system to alert Americans to dangerous conditions they may face this summer. The online heat risk system, presented on Earth Day, combines meteorological and medical risk factors with a simplified seven-day forecast.
The system includes five heat threat categories, with magenta being the worst and deadliest, indicating rare and/or long-duration extreme heat with little to no overnight relief. Red, the second-highest category, represents a major risk that can harm anyone without adequate cooling and hydration, and has impacts on the health care system and some industries. The other categories are pale green (little to no risk), yellow (minor risk), and orange (moderate risk).
The categories are based on strict science-set numerical thresholds, similar to the Saffir Simpson hurricane scale. The thresholds were calculated using local weather data, climatology, and health and medical data specific to each location and time of year.
Heat is the leading cause of weather-related deaths in the United States, with more than 120,000 people taken to the emergency room last year due to heat-related illnesses. The new heat risk system aims to simplify and communicate the risks associated with extreme heat, helping people understand and take necessary precautions.
Both the National Weather Service and CDC will feature versions of the tool on their websites, allowing users to enter a ZIP code for more focused health risks and air quality information, as well as detailed forecasts and explanations.
Health officials emphasize that even as heat waves become more severe due to climate change, society can reduce deaths through better warnings and planning. Doctors should discuss precautions with vulnerable patients before the summer begins, as some medications can interact with outdoor heat.
The Weather Service’s seasonal forecast for May and June shows likely above-average temperatures for much of the United States, indicating an increasingly serious situation as heat waves become hotter, longer, and more frequent, with less relief at night.
The Associated Press contributed to this article.