A tornado watch is issued when weather conditions favor the formation of tornadoes, for example, during a severe thunderstorm.
A tornado warning is issued when a tornado funnel is sighted or indicated by weather radar.
You should take shelter immediately.
Stay tuned to local radio and TV stations or a National Oceanographic and Atmospheric Administration (NOAA) Weather Radioexternal icon for further weather information.
Watch the weather and be prepared to take shelter immediately if conditions worsen.
Signs of an Approaching Storm
Some tornadoes strike rapidly, without time for a tornado warning, and sometimes without a thunderstorm in the vicinity. When you are watching for rapidly emerging tornadoes, it is important to know that you cannot depend on seeing a funnel: clouds or rain may block your view.
- A dark or green-colored sky
- A large, dark, low-lying cloud
- Large hail
- A loud roar that sounds like a freight train
If you notice any of these weather conditions, take cover immediately, and keep tuned to local radio and TV stations or to a NOAA weather radioexternal icon.
Sighting a Funnel Cloud
If you see a funnel cloud nearby, take shelter immediately. However, if you spot a tornado that is far away, help alert others to the hazard by reporting it to 911 before taking shelter as described later. Use common sense and exercise caution: if you believe that you might be in danger, seek shelter immediately.