Minnesota gets a lot of severe weather alerts this time of year, and it can be hard to keep track of what they all mean. Here's a breakdown to help you be prepared – from most serious, to least serious.
A warning is the most serious type of severe weather alert, and can be used for severe thunderstorms, tornadoes and flash flooding.
When a warning is issued, it means a severe weather event is imminent or happening in the warning area, and you should get to a safe place ASAP.
– A tornado warning is issued after a tornado is seen by a spotter, or if one is indicated on weather radar. The warning will include where the tornado is and what towns are in its path, with the alert typically lasting 30 minutes for each specified area, the National Weather Service says.
– A severe thunderstorm warning is issued when radar or a spotter reports a severe thunderstorm. ("Severe" is defined as producing 1-inch or larger hail, or winds are at least 58 mph). The warning will include where the storm is located, what towns will be affected, and the primary threat associated with the storm. The alert usually lasts an hour for each specified area. And remember, severe thunderstorms can produce tornadoes without warning, so they should be treated like a tornado warning.
– A flash flood warning is issued to let people know that flash flooding (so sudden, quick floods – not days of flooding) is either in progress, imminent or highly likely. The warnings can be issued with tornado and severe thunderstorm warnings if torrential rains accompany the storms.
Know that a severe weather warning can be issued without a watch already being in effect.
A watch means dangerous weather (including severe thunderstorm, tornado or flooding) could happen. It's to let people who are in the watch area know they should pay attention to the forecast in case things turn more severe.
The watch will include information about what type of weather you could experience (high winds, hail, lightning, heavy rain, tornado), and the likelihood it will happen. They're usually issued way before severe weather starts, and are in effect for about 4-8 hours, the weather service says.
When a watch is issued, you can keep doing what you're doing. But weather officials urge you keep an eye on the forecast (stay tuned to local media or the National Weather Service's website, or sign up for one of these alerts) and know where to go if the weather gets worse.
When weather does get worse, that's when a warning will be issued. But know sometimes the weather turns severe quickly, and there's not enough time to issue a warning, Homeland Security and Emergency Management says.
Hazardous weather outlook/weather advisory
A hazardous weather outlook or weather advisory are the first steps in the forecast and warning process. When there's convective weather (thunderstorms and tornadoes), the National Weather Service's Storm Prediction Center sends out alerts usually the day before dangerous weather is likely.
These outlooks are then updated as conditions change. For more information on severe weather in Minnesota and how to be prepared, click here.