Justin1569, Wikimedia Commons // CC BY-SA 3.0
Justin1569, Wikimedia Commons // CC BY-SA 3.0

8 Facts About the Biggest Tornadoes on Earth

Justin1569, Wikimedia Commons // CC BY-SA 3.0
Justin1569, Wikimedia Commons // CC BY-SA 3.0

Tornadoes, it turns out, are about as American as apple pie. The United States is home to the majority of all the tornadoes that touch down around the world every year. Most of these twisters are small and only last a couple of minutes, but a small percentage of them can grow enormous and last for many hours, sometimes tearing a path across entire states. The largest tornadoes are in a category all their own as some of the scariest weather conditions nature can create.

1. HUGE TORNADOES REQUIRE HUGE THUNDERSTORMS.

The average tornado is only a few hundred feet wide, but some can be as narrow as a single vehicle or as wide as a mile or more across. The largest tornadoes require immense thunderstorms called supercells in order to form. A supercell is a thunderstorm with a rotating updraft. This rotating updraft helps the storm become strong and resilient. This extra boost gives supercells the ability to produce hail the size of baseballs or larger, intense winds, and enormous tornadoes.

2. THE HOOK BRINGS YOU BACK.

Tornado supercell radar image
A radar image of the supercell that produced a mile-wide F5 tornado near Oklahoma City on May 3, 1999.
Image: Gibson Ridge

Tornadoes usually form in the “hook echo” of a supercell, which is the point where winds wrapping around the storm meet with the updraft racing skyward into the storm. This hook echo is ominously visible on radar imagery and a stunning sight in person. Scientists are still studying why some supercells produce tornadoes and others don’t, but a well-defined hook echo is usually a bad sign that things could get ugly in a hurry.

3. THEY CAN STAY ON THE GROUND FOR A LONG TIME.

Large tornadoes typically have long tracks. Many of these unusually wide storms can stay on the ground for dozens of miles, sometimes traversing several states before finally dissipating. A recent tornado in Wisconsin tracked along a path more than 80 miles long. Unfortunately, when a tornado covers so much ground, it’s more likely to hit populated areas. Many of the tragic tornadoes we’ve seen in recent history caused the amount of damage they did not just because they were intense, but because they covered so much land.

4. SIZE CAN BE DECEIVING.

You shouldn’t judge a tornado solely by its size. Some small tornadoes can produce scale-topping winds, while some big tornadoes are more bark than bite and leave only minor damage—to barns or farm equipment, for example—in their wake. A tornado itself is a rotating column of wind, and it’s the wind that matters. The reason we can see tornadoes is that the low pressure within that column condenses moisture in the air, producing a funnel cloud. If a tornado moves through an area with lots of dust or loose soil, it can make the storm look much larger than it actually is.

5. SOME BIG TORNADOES ARE MADE UP OF SMALLER TORNADOES.

A huge twister can be one terrifying wedge of darkness, but it’s more common for these storms to have several smaller vortices swirling within the larger tornado itself. Storm chasers report this as a "multiple-vortex tornado.” There is some truth to the saying that a tornado can demolish one house and leave the home next door untouched. Some of the worst and strangest damage seen after big tornadoes is attributable to the small, quick “suction vortices” that circulate within a large tornado, sort of like horses going around on a carousel.

6. THE CENTER OF A TORNADO CAN BE RELATIVELY CALM.

If you’ve ever seen the famous final scene of the movie Twister, you’ve probably wondered whether it really is calm and clear in the center of a tornado. It’s not exactly the eye of a hurricane, but the middle of a tornado usually is the calmest part of one of these storms. It’s extremely hard to record (or even see) the inside of a large tornado, but depending on how big it is, the relative lull is likely fleeting and probably still contains gusty winds and flying debris.

7. IMMENSE TORNADOES CAN DO HORRIFYING THINGS.

It’s unsettling to think about what 200-plus mph winds can do when they tear through a populated area. The EF-5 tornado that struck Joplin, Missouri, in 2011 was so strong that it warped and shifted the entire structure of a hospital, requiring its demolition. It’s common to hear reports of trenches scoured into the earth and pavement ripped out of the ground from the intense winds. And there are plenty of accounts of more unusual damage, too, such as thin pieces of wood being driven through a tree trunk or a plastic drinking straw allegedly cutting through a piece of sheet metal.

8. OKLAHOMA IS GROUND ZERO FOR THESE BEHEMOTHS.

The central United States is aptly nicknamed “Tornado Alley” for its tendency to see more tornadoes than anywhere else in the world, and that total includes at least a couple of big, mile-wide tornadoes every year. Central Oklahoma holds the record for both the largest and the strongest tornadoes ever recorded. A tornado that touched down in El Reno, Oklahoma, on May 31, 2013, measured 2.6 miles wide at one point, easily breaking the record for the widest tornado ever observed. Back in 1999, a mobile Doppler weather radar recorded winds of more than 300 mph in an F5 tornado that touched down south of Oklahoma City.

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Why Does the Sky Look Green Before a Tornado?
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A common bit of folklore from tornado-prone parts of the U.S. says that when the skies start taking on an emerald hue, it's time to run inside. But why do tornadoes tend to spawn green skies in the first place? As SciShow's Michael Aranda explains, the answer has to do with the way water droplets reflect the colors of the light spectrum.

During the day, the sky is usually blue because the shorter, bluer end of the light spectrum bounces off air molecules better than than redder, longer-wavelength light. Conditions change during the sunset (and sunrise), when sunlight has to travel through more air, and when storms are forming, which means there are more water droplets around.

Tornadoes forming later in the day, around sunset, do a great job of reflecting the green part of the light spectrum that's usually hidden in a sunset because of the water droplets in the clouds, which bounce green light into our eyes. But that doesn't necessarily mean a twister is coming—it could just mean a lot of rain is in the forecast. Either way, heading inside is probably a good idea.

For the full details on how water and light conspire to turn the sky green before a storm, check out the SciShow video below.

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New Contest Will Give Kids the Chance to Become Weather Channel Meteorologists for a Day
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iStock

Not every kid dreams of being an on-air meteorologist, but for young ‘uns obsessed with storm forecasts and local weather reports, a new contest presents a unique opportunity to live out their dreams. The Mini Meteorologist Contest, sponsored by Lands’ End, will give four kids a chance to present a weather report on The Weather Channel this summer.

The nationwide contest is open to future meteorologists in the U.S. and Canada ages 6 to 16. To enter, they just have to write an essay between 50 and 500 words long on why they love learning about science and weather and why they’d like to be a meteorologist for a day. Four winners will receive a trip for them and their parents to The Weather Channel’s headquarters in Atlanta. They’ll have the opportunity to report the weather for the show on July 12, which happens to be National Summer Learning Day.

The essays will be judged based in equal parts on creativity, grammar, and the entrant’s love of meteorology. The only rules for the essays are that they can’t mention any products or brands other than Lands’ End or The Weather Channel (so no essays about how L.L. Bean inspired your love of cloud formations, kids) and has to be the child’s original work. Kids who are chosen as semi-finalists will have their on-air presentation skills judged in a Skype interview.

Should they win, they’ll get an inclusive trip to Atlanta with media training, a tour of The Weather Channel headquarters, and a $500 Lands’ End gift card to get just the right weather-reporting wardrobe.

The deadline for entering is May 21. Essays can be submitted here.

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