Most Tornadoes Last Under 10 Minutes, but the Danger Runs Longer

Ask A Prepper looks at how long tornadoes stay on the ground and how long the threat around them lasts, drawing on NOAA and National Weather Service data. The piece argues that knowing the timing helps people make better choices once a warning sounds.

Key points

• Typical length: NOAA's Storm Prediction Center says a tornado can last from a few seconds to over an hour, but most end within 10 minutes and travel about 3.5 miles on average.
• Long-track storms: The 1925 Tri-State Tornado covered roughly 243 miles and killed 695 people. The 2021 Mayfield, Kentucky tornado stayed down for nearly three hours along a 165.6-mile path.
• A direct hit: By the article's math, a quarter-mile-wide tornado at 30 mph passes one spot in about 30 seconds, while a mile-wide one takes around two minutes.
• Outbreaks: The April 27 to 28, 2011 outbreak produced 175 tornadoes in 24 hours, so people may have to take shelter more than once over many hours.
• Warning time: Michigan State Police emergency management puts the average warning lead time at 10 to 15 minutes.

Quick take

Ask A Prepper's view is that the danger outlasts any single funnel. It advises using a watch period to get ready, moving to a basement or small interior room once a warning is issued, staying there until the warning expires or officials give the all-clear, and keeping enough supplies for several days of recovery.

Read the full story at Ask A Prepper.