‘Destructive’ storms will trigger emergency weather alerts on phones: How it works

New NWS alert system started Aug. 3

Sample of NWS phone alert.
Sample of NWS phone alert. (NWS/Pexels)

Much like your smartphone alerts you about an AMBER Alert, it will now let you know about certain weather events in your area.

The National Weather Service has implemented a new emergency alert category that will utilize your smartphone’s Wireless Emergency Alert system to let you know about certain severe weather events.

NWS said it developed three categories of damage threat for Severe Thunderstorm Warnings. The categories, in order of highest to lowest damage threat, are destructive, considerable, and base. These tags and additional messaging are designed to promote immediate action, based on the threats.

  • The criteria for a destructive damage threat is at least 2.75 inch diameter (baseball-sized) hail and/or 80 mph thunderstorm winds. Warnings with this tag will automatically activate a Wireless Emergency Alert (WEA) on smartphones within the warned area.
  • The criteria for a considerable damage threat is at least 1.75 inch diameter (golf ball-sized) hail and/or 70 mph thunderstorm winds. This will not activate a WEA.
  • The criteria for a baseline or “base” severe thunderstorm warning remains unchanged, 1.00 inch (quarter-sized) hail and/or 58 mph thunderstorm winds. This will not activate a WEA. When no damage threat tag is present, damage is expected to be at the base level.

NWS said, on average, only 10 percent of all severe thunderstorms reach the destructive category each year, nationwide. Only storms categorized as destructive will trigger a WEA to your cell phone.

All National Weather Service Severe Thunderstorm Warnings will continue to be issued and distributed via weather.gov, NOAA Weather Radio, Emergency Alert System and through dissemination systems to our emergency managers and partners.

Also: SE Michigan weather radar, alerts, updates: Download the WDIV Local4Casters app


About the Author:

Ken Haddad is the digital special projects manager for WDIV / ClickOnDetroit.com. He also authors the Morning Report Newsletter and various other newsletters. He's been with WDIV since 2013.