Fact check: Kentucky tornado had 190 mph winds, according to NWS estimate

Daniel Funke, USA TODAY
·5 min read

The claim: A tornado in Kentucky had wind speeds exceeding 300 mph

At least 88 people were killed in a series of powerful tornadoes that ripped across five states over the weekend. The twisters left thousands of people homeless and many more without heat or water.

Online, some claim one of the deadly tornadoes was close to breaking wind speed records.

"There are still weather events possible this morning in Mississippi, but the damage and destruction from the tornado that hit Arkansas and ran for 250 miles through 4 states is possibly the worst tornado in history," reads a Dec. 11 post from a page called Mississippi News. "300 mph winds, massive damage, mass casualties."

The post accumulated nearly 1,000 shares within five days. Other Facebook users have shared similar claims, with some asserting the tornado, which wreaked havoc across Kentucky, could be classified as an F6.

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That twister was the strongest of the storms surveyed by the National Weather Service. But there's no evidence its wind speeds topped 300 mph – and there's no such thing as an F6 tornado.

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"In science, we say 'extraordinary claims require extraordinary evidence,'" Paul Markowski, a professor of meteorology at Pennsylvania State University, said in an email.

USA TODAY reached out to the Facebook users who shared the claim for comment.

Wind speed estimates not close to 300 mph

The NWS has surveyed dozens of tornadoes that took place Dec. 10-11. None of them are estimated to have reached wind speeds exceeding 300 mph.

"The highest wind speed is 190 mph and that is for the Mayfield (Kentucky) tornado, which is rated EF4," Maureen O'Leary, an agency spokesperson, said in an email.

In this aerial photo, destruction from a recent tornado is seen in downtown Mayfield, Ky., Sunday, Dec. 12, 2021.
In this aerial photo, destruction from a recent tornado is seen in downtown Mayfield, Ky., Sunday, Dec. 12, 2021.

The path of the tornado was at least 163 miles long, according to preliminary NWS estimates. Gov. Andy Beshear said Mayfield, a town in southwest Kentucky, was "completely devastated."

"The word 'estimated' is important, as we do not have the ability to operationally measure tornado wind speeds," Chris Weiss, a professor of atmospheric science at Texas Tech University, said of the NWS estimate in an email. "As such, we have to assess the damage, then associate that damage with an expected wind speed from, e.g., wind tunnel tests."

Formal surveys use those "damage indicators," according to Jana Houser, an associate professor of meteorology at Ohio University. The Enhanced Fujita (EF) Scale, which the NWS uses to rate tornadoes, is based on estimated wind speeds and related damage.

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Houser said in an email that any wind speed estimates differing from the NWS' surveys would presumably come from Doppler radar, which researchers sometimes use to study tornadoes.

For the tornadoes that took place over the weekend, wind speeds estimated via radar were slower than the NWS estimates, according to Houser.

"Radar data are nowhere close to 300 mph," she said. "The strongest that I could find was actually only 134 mph."

In the past, radar measurements – which Houser said tend to underestimate wind speed – have recorded tornadoes with winds around 300 mph. But that's rare.

"There were only two times where this has been confirmed via high-resolution, research-grade mobile radar measurements," Houser said.

In May 1999, a tornado outbreak in Kansas and Oklahoma produced a twister with wind speeds exceeding 300 mph. Another tornado, which occurred in May 2013 in Oklahoma, produced slightly slower winds.

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Aside from radar and NWS estimates, on-the-ground surveys of damage from the recent tornadoes do not support claims of 300 mph winds.

"We had four people from our research group out in the field doing damage surveys and some engineering analyses based on failures we saw in the most heavily damaged areas," Frank Lombardo, an assistant professor of civil and environmental engineering at the University of Illinois at Urbana-Champaign, said in an email. "Based on the analysis we’ve done, there is no evidence of 300 mph winds in the places we surveyed."

Our rating: False

Based on our research, we rate FALSE the claim that a tornado in Kentucky had wind speeds exceeding 300 mph. Preliminary estimates from the NWS indicate the storm had wind speeds of about 190 mph. Experts say there's no evidence to suggest the tornado had 300 mph winds, which are rare.

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This article originally appeared on USA TODAY: Fact check: Kentucky tornado wind speeds weren't estimated at 300 mph