Safety guide
Tornado watch vs. warning
The two alerts sound similar but demand completely different actions. Here is what each one means and exactly what to do.
The short answer
A tornado watch means conditions are favorable for tornadoes to form, so be ready. A tornado warning means a tornado has been spotted or indicated by radar, so take shelter immediately.
Tornado watch
Issued by the NOAA Storm Prediction Center (SPC), typically covering a large area (often several counties or states) for 4 to 8 hours.
- What it means: atmospheric conditions (wind shear, instability, moisture) support tornado development. No tornado has been confirmed.
- What to do: review your shelter plan, charge your phone, keep alerts on, move outdoor items inside, and know where your safe room is.
Tornado warning
Issued by your local National Weather Service office, usually for a small area (part of a county) for 30 to 60 minutes.
- What it means: a tornado has been sighted by storm spotters or indicated by weather radar. It is happening now or imminent.
- What to do: go to a basement or an interior room on the lowest floor, away from windows. Cover your head and neck. If you are in a vehicle or mobile home, get to a sturdy building or lie in a ditch. Do not wait to see the tornado.
In an emergency
Tiah is informational only and is not a replacement for official emergency services, the NWS, or ECCC. In an emergency, call 911.
How Tiah gives you earlier context
Official watches and warnings are essential, but they arrive at specific moments. Tiah's TTRF engine continuously fuses SPC outlooks, live CAPE and shear, and climatology into a 0 to 7 hour tornado risk view, so you can see conditions building before a watch is even issued. The Alert Center then surfaces every NWS and ECCC watch and warning the moment it is published, filtered by severity and threat type.