How common are destructive tornadoes in December? Perhaps more than you think

As a powerful storm system unleashed tornadoes in Oklahoma and Texas, you might be wondering if a December tornado outbreak is out of the ordinary.

Tornado season in the southern Plains — the time that tornadoes are most likely to hit — spans from May through early June, according to the National Severe Storms Laboratory.

“But, remember, tornadoes can happen at any time of year,” officials said.

In December 2021, at least 61 tornadoes hit the central and southern U.S. within eight days, the National Oceanic and Atmospheric Administration reported.

The tornadoes ripped across eight states, killing more than 80 people and causing “devastating damage to communities,” officials said at the time.

“The very fact that tornadoes of this intensity struck in late autumn, rather than in the spring and summer when thunderstorms and tornadoes are more likely, is remarkable,” NOAA said.

Are December tornadoes rare?

Research from the agency estimates about a 12% to 15% chance that a tornado would occur on a December day in the U.S.

In June, the likelihood increases to 90%, NOAA said.

Following the December 2021 outbreak, Illinois News Bureau physical sciences editor Lois Yoksoulian said she spoke with University of Illinois Urbana-Champaign atmospheric sciences professor and department head Jeff Trapp about the timing of the severe storms.

During the interview, Yoksoulian asked if there are more tornadoes occurring in “off season” winter months, including December.

“I reanalyzed the tornado data from the past 40 years and found that the only months in the U.S. that have experienced a robust positive trend in tornado activity are December and January,” Trapp said. “So yes, this is indeed factual.”

He described December tornado outbreaks as “rare but not unprecedented.”

A tornado outbreak on Dec. 26, 2015, killed 11 people in North Texas and caused destruction from Hill County to Colling County. The tornado that hit Garland that day was the worst, an EF-4, with wind speeds of 166-200 mph damaging at least 600 structures.

Are December tornadoes often destructive?

While not as common as a spring or summer tornado, NOAA said December tornadoes can still be significantly destructive. From 1879 to December 2021, 22 violent EF-4 and EF-5 tornadoes have hit in December, officials said. EF-4 and EF-5 tornadoes are considered the most destructive.

“These cool-season tornadoes are also potentially more impactful because they have a higher tendency to be very fast-moving storms that occur after sunset, while people are at home sleeping – unaware of the impending danger and need to act quickly – as was the case with many of the Dec. 10 tornadoes,” Trapp said.

What causes December tornadoes?

During last year’s severe storms, NOAA said warmer temperatures contributed to their development. Still, the agency said it’s difficult to link tornadoes to climate change.

“Because less than 10% of severe thunderstorms produce tornadoes, it is difficult for scientists to draw conclusions about the processes that lead up to tornadoes and their potential connections to climate change,” officials said. “Additionally, there needs to be a better understanding of how certain features of the environment that contribute to tornadoes will change in the future.”

Before hitting Texas, major storm unleashes tornado in Oklahoma. Photos show damage

Tornado damage updates: See photos, video from Decatur, Grapevine in North Texas

North Texas weather: At least 5 tornadoes damage Grapevine, North Richland Hills, Decatur