Confirmed: December Broke National Tornado Record

Lightning illuminates the nighttime and deadly tornado
in Kentucky last month that all but destroyed the city of 
Mayfield. The United States broke the record for the
most tornadoes in December by a large margin. 

As of the end of last week, meteorologists counted 217 tornadoes in the United States during December, far and away the most on record for that month. 

On average, just 24 tornadoes hit the United States in December. 

Cold air descending from Canada on a regular basis tends to squelch warm, humid air from the Gulf of Mexico from invading the United States. No humid air, no tornadoes.

This year, that unseasonably muggy, warm air often had unfettered access deep into the heart of the United States. 

December turned out to be by far the Lower 48's warmest on record, and the warmth was most focused on the Southeast and Midwest. When the usual December storms smacked into this summer-like air, that created a perfect recipe for tornadoes.

Tornadoes happened throughout the month, but two large outbreaks on December 10 and December 15 comprised the bulk of them. The December 10 outbreak caused incredibly strong tornadoes for so late in the season, including an EF-4 that traveled 161 miles and killed 76 people in and near Kentucky. It was the deadliest December tornado in U.S. history. 

The December 15 outbreak featured tornadoes that were oddly far north. Prior to 2021, there had been no known confirmed tornadoes in Minnesota during December. On December 15, there were 16 of them.  

For the year as a whole, the United States has about as many tornadoes as usual, with a preliminary total of 1275.  Depending on who's studying these things, normally there's somewhere between 1250 an 1350 tornadoes annually in the United States.  

The usual spring peak of tornado season was somewhat quieter than usual. However, in addition to December, March, August and October. 

Of course, there's no telling how 2022 will turn out in terms of tornadoes.  In January, the United States has on average about 35 of them. As of Monday, the United States already has a preliminary count of 22 tornadoes so far this month.