December’s largest tornado outbreak killed dozens of people

December’s most prolific tornado outbreak on record unfolded across portions of the central United States in 2021.

Dozens of twisters touched down from Mississippi to Indiana between Dec. 10 and Dec. 11, including one of the longest-track tornadoes ever observed.

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A rare and dangerous December tornado outbreak

Conditions turn cold and snowy across much of North America as December settles across the continent. But intrusions of warm and humid air can surge northward when a powerful storm system arrives, and that’s exactly the setup we saw heading into Dec. 10, 2021.

A strong Colorado low moving toward the Great Lakes set the stage for a violent tornado outbreak beginning that evening. Unstable air surging north provided the instability needed for thunderstorms to erupt around the Mississippi River.

Several long-lived supercell thunderstorms produced families of destructive tornadoes across the region through the overnight hours. Experts found 71 tornadoes in all, making this the most prolific December tornado outbreak on record.

That wasn’t the only tragic record broken by this outbreak.

A historic, long-lived tornado

One particularly intense storm left a trail of destruction across four states, producing two EF-4 tornadoes that carved a path from northeastern Arkansas through central Kentucky.

The dominant tornado touched down in Woodland Mills, Tennessee, at 9:49 p.m. local time. Intensifying almost immediately, the storm made a direct hit on Cayce, Kentucky, at 10:01 p.m.

Continuing northeast at a steady pace, the powerful EF-4 tornado’s intensity peaked as it caused widespread devastation in the town of Mayfield, Kentucky, about 25 minutes later.

Forecasters tracked the large tornado as it sliced through the woods and farms of western Kentucky, leaving behind a scar visible on satellite imagery.

Dawson Springs suffered extensive damage just before 10:30 p.m. local time, and the storm would continue for more than an hour before finally lifting south of the Ohio River.

All told, the twister that levelled Mayfield remained on the ground for 271.2 kilometres, making it one of the longest-tracked tornadoes ever observed.

Tragically, the tornado outbreak claimed 89 lives across the hardest-hit areas, cementing the event's status as one of this century’s deadliest tornado outbreaks.

Header image courtesy of the U.S. National Weather Service.

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