November 30, 2020

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Dangerous Straight-line Winds Are More Common Than Tornadoes. Here’s What You Should Know About Them.


Andrew Kling was home in his Kansas City apartment talking on the phone to his partner when a strong storm kicked up.

Curious, he went to the living room to get a better look out the window when he heard a loud crash. Then there was a flash of light, then the power went out.

Because of the light flash, he assumed there must have been a lightning strike nearby, but when he walked back into his bedroom, he realized it was something altogether different: : A massive wooden bean had shot through the brick wall of his apartment and landed right in his bedroom. Later he would learn that it wasn’t just this beam — half the apartment building’s roof had been torn off and some of it had landed on a power transformer, causing the outage.

“The fire department arrived and gave me five minutes to grab what I could and leave,” Kling says. “As I rushed through the sudden and bizarrely alien landscape of my apartment, [I noticed] the plaster dust in the air was lit by a street light shining through the window and the firefighter’s headlamp.”

“It was wild how just minutes earlier I was getting ready to read a book and enjoy a refreshingly free night with no commitments — so much for that.”

All Kling took with him were some clothes, his passport and birth certificate, his mother’s guitar and, he says, “for some reason, a half a bottle of barbecue sauce.”

As he drove away from his apartment building, he was struck by the fact that his building was the worst hit of any place in the neighborhood. “There were some tree branches that had been blown off, but they were tiny compared to the gaping maw of where our roof used to be.”

What Kling experienced was a microburst, a type of straight-line wind incident.

What are straight-line winds?

“Straight-line winds are a significant push of air in one direction usually associated with thunderstorms,” explains Jonathan Belles, digital meteorologist at Weather.com. “These winds don’t swirl like a tornado does, but can still cause significant damage to trees, signage, canopies, and in some cases, homes.”

Tornado or straight line winds took trees down and tipped some over at Anoka County Parks in Minnesota.

(STORMI GREENER/Star Tribune via Getty Images)

According to the National Weather Service, these damaging winds are actually more common than tornadoes, though the damage a straight-line wind causes is often erroneously attributed to tornadoes.

Damage and debris from straight-line winds are often found in a straight line — hence the name.

Trees on land near Snowbank Lake outside of Ely show the effect of the strong northwest straight-line winds that blew through the area July 4th of 1999.

(MARLIN LEVISON/Star Tribune via Getty Images)

Straight-line winds are usually either the outflow from strong to severe thunderstorms (downbursts or microbursts), Belles says, or they occur along a line of thunderstorms (derechos).

According to the National Severe Storms Laboratory, these damaging winds exceed at least 50-60mph.

“The most severe straight-line winds can blow over 100 mph for short periods of time,” says Belles. These kinds of straight-line winds usually come with heavy rainfall or even large hail, which can punch holes in homes, buildings and vehicles.

Severe hail storm works its way across the high plains of Kansas, USA

(john finney photography/Getty Images)

“Strong winds can occur any time of the year, but they are usually caused by a strong jet stream or strong heating of the ground that allows storms to grow,” explains Belles.

What are microbursts?

“When thunderstorms collapse, like a house of cards, all of the air falls out of them, gaining momentum as they hit the ground and then spread out in all directions,” Belles explains. This is called a downburst or a microburst, which is what Kling had experienced.

Microbursts are relatively smaller downbursts, which can last anywhere from a few seconds to minutes and can reach speeds up to 100 mph — which is roughly equivalent to an EF1 tornado — and generally affect an area of 2.5 miles or less.

Damage to Arkon, Colorado after a microburst June 8, 2020

(Twitter/@kiarajanaeguy3)

They happen all over the United States, but they’re most common east of the Rocky Mountains in the Great Plains region that get a lot of thunderstorms.

Microbursts can be particularly dangerous to aircrafts, especially during take-off and landing. They are also not easy to detect on radar, which means they often seem to come out of nowhere for pilots.

Damage to Arkon, Colorado after a microburst June 8, 2020

(Twitter/@kiarajanaeguy3)

For example, in August 1985, a microburst is believed to have caused the crash of Delta Airlines Flight 191, which killed 137 people. A strong downburst is believed to have violently knocked the landing plane to the ground, short of the runway, hitting a car on a highway just north of the airport, then bouncing the plane to the field, where it plowed into two large water tanks and caught fire.

What are derechos?

In spring and summer, thunderstorms can organize into derechos, which are, according to Belles, the highest classification of straight-line winds.

“They are walls of wind that develop from groups of thunderstorms that are pushed in one direction and can travel hundreds of miles, sometimes thousands, across the country bringing damaging wind gusts.”

A storm is classified as a derecho, according to the National Weather Service, if the damage swath from the wind wall extends more than 240 miles, and if the wind gusts were 58 mph or stronger at most points along the storm path.

However, derechos can reach stronger wind speeds too. For example, on the morning of May 31, 1998, a derecho swept across Wisconsin and Lower Michigan and produced gusts up to 130mph.

How do you stay safe?

While tornadoes and straight-line winds are different, both are very dangerous. Much like tornadoes, it’s difficult to predict exactly when straight-line winds might hit. Instead, forecasters generally look for the conditions that might be favorable for straight-line winds to form.

Extreme weather with this tornado-warned thunderstorm Supercell storm displaying a large downburst of monsoon like torrential rain, Colorado. USA

(john finney photography/Getty Images)

“We do typically have more lead time on straight-line winds than we do for tornadoes, ranging from 15 minutes to a couple hours,” says Belles.

The safety precautions that you should take for straight-line winds are also similar to those for tornadoes:

  • Take severe thunderstorm warnings seriously.
  • Find shelter immediately if you’re outside — or if you aren’t anywhere near shelter, crouch down to the lowest spot that you can find.
  • If you’re driving, pull over to a safe area with your vehicle facing the direction of the wind.
  • If there’s time, bring in loose items from outside including any outdoor furniture, toys or bicycles.
  • Stay away from powerlines and trees that could fall on you.
  • If you’re home, go to the lowest level of your home and keep away from windows.



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