Tennessee gets more tornadoes at night than any other state. Here's why (2024)

Rachel Wegner|Nashville Tennessean

Overnight tornadoes strike Tennessee more than anywhere else in the United States.

The Volunteer State also has the most nighttime tornado fatalities in the country. Spotting tornadoes after dark, especially if they are rain-wrapped, and waking people up to alert them factor into that statistic, National Weather Service Nashville meteorologist Krissy Hurley said. The state's population density also plays a part.

FATALITIES: Tennessee led nation with highest number of tornado deaths in 2020

In March 2020, overnight storms spawned 10 tornadoesin Tennessee, including an EF-3 in Nashville and an EF-4inPutnam County. The tornadoes killed 25 people and injuredhundredsstatewide on March 2 and 3. By the end of that year, Tennessee also led the nation in overall tornado deaths.

But what causes nearly half of Tennessee's tornadoes to strike after the sun goes down? Three experts offera look at the science behind it all.

TORNADOES IN TENNESSEE: What to know, understand and remember

Experts: A'potpourri' of factorsdrive night tornadoes in TN

Storms passing through the South don’t dissipate as quickly in the evening as they might in the Plains, where less moisture is available to insulate warmth.Hurley said lingering moisture from the Gulf of Mexico can be a tipping point for storms in Tennessee.

"It’s an ample source of moisture. It’s never going away —it doesn’t matter if we hit sunset, it doesn’t matter if it’s in the middle of the day," she said. "Once it makes it up here, it tends to stay here.”

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Atmospheric scientist and disaster geographer Walker Ashley said states like Texas and Oklahoma in "tornado alley" typically see most tornadoes in May and June. But in Tennessee and across the Midsouth, that season stretches from November to April.

"That happens to be a time of year where day length is at a minimum," said Ashley, who is a professor at Northern Illinois University."So naturally, your odds of a tornado at night are much higher."

He also pointed to the prevalence of quasi-linear convective system —or QLCS — events in Tennessee. Simply put, they are lines of fast-moving storms that are not perfectly straight and can cause tornadoes. QLCS events include things like squall lines and bow echoes, which can both pack powerful winds.

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Ashley said QLCS events often occur in the evening and overnight hours, and the region fromthe Ohio River valley down to the Tennessee River valley tends to have more QLCS events than the rest of the country.

"It's like a potpourri of things that can create tornadic environments," he said.

Kelsey Ellis, aprofessorat theUniversity of Tennessee in Knoxville and an expert on hazardous weather climatology,said it's important to understand what it takes to form a tornado to get a clearer picture of what's happening in Tennessee.

Instability, or air that wants to rise, is akey ingredientto form a strong thunderstorm and possible tornado.

"If you're standing near a strong thunderstorm, you may feel warm air at your back flowing into and feeding the storm," Ellis said. "Greater instability helps make that happen."

Wind shear is another key factor, which is how wind speed and direction change with height. There is morewind shear in the South than the Plains, according to Ellis. That allows nighttime and cool season tornadoes to happen even without substantial surface heatand energy.

How to stay weather aware in Tennessee

Given the likelihood of severe storms and tornadoes in Tennessee, especially at night, weather experts and public officials emphasize the importance of weather awareness.

It's a good idea to havemultiple ways to receive weather updates, like a storm alert appor a weather radio that will wake you up. You can also formulate an emergency plan and designate a "safe room" to shelter from storms.

"If you get separated from family, make sure you have a place to meet or have an out-of-town contact to let know you are OK," the NWS said.

HOW TO PREPARE FOR SEVERE WEATHER: Safe rooms, weather alerts, supplies

Keeping a bag packedwith supplies like food, water, extra clothing, shoes, necessary medicine, flashlights and extra batteries is also a good practice.If a storm knocks out the power, familiarize yourself with carbon monoxidesafety measures before firing up a generator.

"Weather may not be on the forefront of what’s going on in your life," said NWS Nashville meteorologist Scott Unger."But, especially in the South, it needs to be."

Find reporter Rachel Wegner at rawegner@tennessean.com or on Twitter @rachelannwegner.

Tennessee gets more tornadoes at night than any other state. Here's why (2024)

FAQs

Tennessee gets more tornadoes at night than any other state. Here's why? ›

There is more wind shear in the South than the Plains, according to Ellis. That allows nighttime and cool season tornadoes to happen even without substantial surface heat and energy.

Why do Tennessee tornadoes happen at night? ›

“In the southeast especially, we see a lot of overnight tornadoes,” Husted said. “That's because we get the low-level jet that helps us stay a little more mixed in the atmosphere at the ground, and that allows those tornadoes to continue to be a potential threat.

Which state has the most tornadoes at night? ›

Southern states such as Tennessee, Kentucky and Arkansas also see more tornadoes overnight versus any other state. This can lead to higher fatalities, since many people are sleeping and unaware that a tornado is approaching.

Why are tornadoes worse at night? ›

Tornadoes at night are much more dangerous since you can't easily see them. It takes lots of lighting to illuminate tornadoes after dark.

Is Tennessee the new Tornado Alley? ›

Only three whole states are part of tornado alley: Oklahoma, Kansas and Missouri. Parts of Louisiana, Iowa, Nebraska, eastern Colorado and the northern part of Texas are considered part of the alley. Tennessee is not considered part of tornado alley, but the state has had its fair share of tornadoes over the years.

What city in Tennessee has the most tornadoes? ›

Which city in Tennessee has the most tornadoes? Shelby County — home to Memphis — sees the most tornadoes each year, totaling 56 twisters from 1950 to 2022.

Where to live in Tennessee to avoid tornadoes? ›

On average, East Tennessee does get fewer tornadoes than the middle and western parts of the state. That's because those other areas are flatter and more exposed, University of Tennessee climatology professor Kelsey Ellis explained to the Tennessean in 2021.

What is a nighttime tornado called? ›

Nocturnal tornadoes are dangerous and deadlier because, most of the time, people are asleep and don't know they are coming. Learn how to prepare and stay safe.

Why do you lay down during a tornado? ›

In the open outdoors: If possible, seek shelter in a sturdy building. If not, lie flat and face-down on low ground, protecting the back of your head with your arms. Get as far away from trees and cars as you can; they may be blown onto you in a tornado.

How to tell if a tornado is coming at night? ›

These include:
  1. Dark, Green Sky. If you spot dark clouds on the horizon or a green-tinted sky, take it as a signal that a tornado could be coming and that you should be aware and cautious. ...
  2. Funnel-Shaped Cloud. A funnel cloud is probably the most obvious sign of a tornado. ...
  3. Approaching Cloud of Debris.

How many tornadoes has Tennessee had in 2024? ›

Tennessee Tornado Stats
Tennessee Tornado Totals by Year
YearTN Total TornadoesMiddle TN
2024 (as of July 31, 2024)1714
202340*21*
202251
76 more rows

How prone is Tennessee to tornadoes? ›

Tennessee is a state that fortunately does not have a high average of tornadoes during the year compared to states that are in Tornado Alley, which consists of states from Texas to Nebraska. According to the National Oceanic and Atmospheric Administration, Tennessee sees the highest number of tornadoes in April.

Is Tennessee a good place to live? ›

Tennessee offers a unique blend of history, culture, affordability, and natural beauty, making it an ideal place to live. From the bustling cities of Nashville, Memphis, and Chattanooga to the tranquillity of the Great Smoky Mountains National Park, there's something for everyone in Tennessee.

What are nighttime tornadoes called? ›

Nocturnal tornadoes are even more dangerous and deadlier because they happen under cover of darkness, and people often don't know they are coming or can't see them. It also makes it harder to receive warnings, assess the danger and take protective action.

What are the worst months for tornadoes in Tennessee? ›

According to the National Weather Service, Tennessee sees most of its tornadoes from March to May. During this time, the seasons are changing from the cold air of winter to the warm air of spring and summer.

How rare is a tornado in Tennessee? ›

Tornadoes in Tennessee

There have been 14 tornadoes in the Nashville/Davidson County area since 1974 and 11 tornadoes since 1994, and that includes three tornadoes in 1998 and one tornado in 2020 that caused major damage in several parts of the city.

At what time of day are tornadoes most common Why? ›

While tornadoes can occur at any time of day, they are more frequent in the afternoon and evening, when the heat of the day has produced the hot air that powers a “tornadic thunderstorm”. Tornadoes are most common in the United States, but they also occur in other parts of the world, including India and Bangladesh.

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