Tornadoes are among the most destructive forces in nature. They can level well-built structures, uproot trees, toss semitrucks — and be deadly. They are most common in the US Plains and Southeast, but have been reported in all 50 states. They can happen anytime during the day or night, so knowing the difference between a tornado watch and warning could mean the difference between life and death. The Storm Prediction Center and local National Weather Service offices closely monitor developing thunderstorms and will issue a watch or warning if the storm warrants an alert.
A tornado watch is issued by the Storm Prediction Center. It means that conditions are favorable for a potential tornado. “This highlights an area and usually alerts for the next four to six hours where risk is increasing,” said Bill Bunting, chief of forecast operations at the prediction center. If a tornado watch is issued, you should have your supplies, choose a safe place and have a plan in place — just in case a tornado develops. This does not mean there is a tornado. This only means to be on watch and stay informed about the weather in your area in case things intensify.
A tornado warning means a tornado has been sighted, or that there is a strong indication on radar that a tornado is in progress. “When a particular area (is) under an immediate risk, then the local office will issue a warning and that’s the call to action,” said Bunting. If a tornado warning is issued for your area, you should immediately seek shelter and get to your safe place until the tornado threat has passed. This means a tornado is imminent. There’s a third type of tornado alert that trumps them all. The tornado emergency was added in 1999 and it’s basically a tornado warning on steroids. If a tornado is in progress and will have a significant impact to human life, with catastrophic destruction to property, a tornado emergency will be issued.