New emergency mobile phone alerts for severe thunderstorms

Science & Technology

Severe thunderstorms can strike at any time, anywhere. Whether it be a tornado, strong winds, or large hail, there is always a concern of damage and destruction. The National Weather Service is taking steps to add more damage categories to severe thunderstorm warnings to more clearly show the severity and potential impacts from these thunderstorms. These tags and additional messaging are designed to help people better understand what the threats are with severe thunderstorms so they can quickly take action to protect themselves.

Example image provided by the National Weather Service

The National Weather Service will use the new tags and additional messaging for Severe Thunderstorm Warnings starting August 2nd. The categories, in order of highest to lowest damage threat, are destructive, considerable, and base.

  • 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.

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