Powerful Tornadoes Leave at Least 70 Dead Across 6 States

“I’d be surprised if we don’t see at least five or more” counties with deaths, Beshear said at a news conference. On Saturday morning, he estimated there could be more than 100 dead, which would make this Kentucky’s deadliest tornado.

Blankenship said Monette is without power. That’s also true for more than 300,000 households in states hit by the tornadoes and another roughly 100,000 in other parts of the Midwest.

A Record-Setting Tornado Caused Much of the Damage

Multiple tornadoes touched down on Friday night amid the severe weather outbreak. But one twister, which has been dubbed the “quad-state tornado,” caused most of the damage—and it could be a record-setting tornado.

The tornado tore across a 240-mile (386-kilometer) stretch that included both Monette to Mayfield. Storm investigators with the National Weather Service will look to see if it remained on the ground the whole time. If it did, it would be the longest tornado track ever recorded in the U.S.

While official ratings are forthcoming, Beshear said this was the “most severe tornado event in Kentucky’s history.” The NWS investigators will do a formal analysis to officially rate the tornadoes, but radar data captured on Friday night shows that the storm could have been an EF-4 on the Enhanced Fujita Scale and images on the ground bear it out as well. That would make it a “violent” tornado and place its winds between 166 and 200 mph (267 and 322 kph). There have only been three December EF-4 tornadoes in U.S. history.

Bizarre Weather Set the Stage for the Tornado Outbreak

Tornadoes require atmospheric instability to form. In the U.S., that usually means cold fronts ushering in storms from the West and warm, humid air rising up from the Gulf of Mexico. That provides both the energy needed for violent winds to whip up and enough wind shear to cause storms to twist as the front heading east intersects with the Gulf air moving north. While tornadoes can form in any month, winter is usually a relatively quieter period because air over the Gulf isn’t warm enough to provide the necessary fuel.

But the Gulf has maintained warmth and sent it streaming up to the eastern U.S., right as a powerful cold front that brought heavy snow to Colorado swooped out of the West. To give a sense of the opposing temperatures on either side of the front, it was 80 degrees Fahrenheit (27 degrees Celsius) in Memphis and 30 degrees Fahrenheit (minus-1 degree Celsius) in Minneapolis. These clashing masses of air unleashed the historic outbreak of storms.

In addition to tornadoes, the storm system also lit up the skies with lightning and sent hail raining down. Data from Vaisala, a meteorology company, detected more than 782,000 bolts of lightning, making this a rare event by that measure as well. Vaisala meteorologist Chris Vagasky tweeted this ranks as one of the 10 largest December lightning outbreaks since at least 2015.

The Climate Conditions Behind the Severe Weather

A few climate factors are likely at play as well. This fall, La Niña formed. The natural climate pattern in the tropical Pacific can rearrange weather globally, including increasing the odds of more winter twisters in the exact region that saw an outbreak Friday night.

The exact influence climate change is having on tornadoes is hard to pin down, though research does indicate large clusters of twisters are becoming more common. It’s a very active area of research, though.

But as with anything tied to extreme heat, it’s impossible to talk about it without talking about the influence of burning fossil fuels. The rise in the global average temperature means freak heat has become both more common and severe. We’ve seen it time and time again to the point where it’s impossible to talk about abnormal warmth without mentioning climate change. The warm air currently flooding the South will push north and will bring spring-like conditions to the Northeast next week.

This is a developing story and will be updated.