More tornadoes touch down across South Carolina's Midlands than elsewhere in the state. And more of the stronger ones, too.

But the popular tag for the stretch, "Carolina Alley," is misleading, climate researchers say.

There have been clusters of tornadoes in spots through the middle of the state over the past 70 years or so, but they have been spread over a large area. Smaller pockets have occurred across the Upstate. 

Tornadoes have touched down in every one of the state's 46 counties.

"We haven't looked at (the Midlands being a focus) because we're trying to educate about the threat statewide," said State Climatologist Hope Mizzell.

"It's not whether the state has a 'Tornado Alley,' " she said. "We obviously are vulnerable. We have experienced tornadoes and have experienced them in every month of the year."

The Southeast is moving into spring, a volatile change of seasons when the friction from clashing cold and warm air currents tends to fire up thunderstorms more frequently over most of the country. Those storms spin up tornadoes.

Earlier this month, one of those changes churned powerful storms that tore across the South. The blows spawned tornadoes that killed at least 23 people in Alabama, then swept into South Carolina to spawn at least three more. Strong winds knocked down trees, damaging some roofs and vehicles.

For people lulled to complacency by a relatively mild winter, the blast was a scary wake-up call. It wasn't so shocking to meteorologists or researchers.

April and May are the months South Carolina has experienced the most tornadoes over the past 70 years. But March has been just about as bad, and September as bad as March because tornadoes can be spun off tropical storm systems.

The state has seen an average 14 tornadoes per year since 1950, mostly in the weaker scales of the storms, according to the S.C. Climate Office. 

"Every dot on that map is a tornado that potentially traveled as far as 3 miles," Mizzell said about her office's plotting of 995 tornadoes since 1950.

There’s no record of a tornado with winds stronger than 200 mph ever touching down anywhere in the state. But all 10 of the tornadoes with winds stronger than 165 mph have struck in the Midlands. More than two-thirds of the 30 storms with winds stronger than 135 mph also hit the Midlands.

"Tornadoes are definitely part of our hazards mix in the Carolinas," said University of South Carolina geographer Greg Carbone. "Yes, when they occur in the Carolinas, it is predominantly in the Midlands swath."

Some say the average number of tornadoes in the state has increased in recent decades, but Mizzell and others said that likely is due to more precise studies of storm damage.

"Carolina Alley" is just the tail end of a larger, more disturbing phenomenon. Researchers are starting to focus on what's popularly called "Dixie Alley" — a stretch of the South from Louisiana through Tennessee where the storm earlier this month became a monster before sweeping into South Carolina.

A multi-university study in 2018 indicated the number of tornadoes increasing in the region during the colder months from November to February, while decreasing across the Great Plains' notorious "Tornado Alley."

That finding and others leave analysts trying to parse out if tornadoes in general are starting to form farther East than in the past, or if there's just more documentation with more research.

The number of tornado-forming storms across the region doesn't appear to be increasing, but more twisters appear to be forming in the storms that spin them up, Florida State University geographer James Elsner told Public Radio International after the outbreak earlier this month. Elsner suspects the warming climate is fueling that.

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Reach Bo Petersen at @bopete on Twitter or 843-937-5744.

Science and environment reporter. Author of Washing Our Hands in the Clouds.