Tornadoes have the connotation of scary, dark funnel clouds which move over farmlands in Kansas, Oklahoma, and Texas, destroying everything in its path. When the word “tornado” is mentioned, dramatic images from The Wizard of Oz or Twister sometime come to mind. While tornadoes, in fact, do appear most prominently in heart of Tornado Alley (Texas, Oklahoma, Kansas, Nebraska, eastern Colorado, and South Dakota) and decimate everything in their paths, tornadoes can happen just about anywhere in the U.S. and on any continent in the world (excluding Antarctica) and have various intensities, duration, qualities, and paths.

To give a basic explanation on tornadoes, a tornado (or twister) is a “violently rotating column of air that extends between the Earth’s surface and a cloud, usually a cumulonimbus cloud.” Most intense tornadoes result from the development of supercell thunderstorms, which are fueled by cold, dry air aloft and warm moisture closer to the surface. Wind shear, updraft (buoyant warm air lifts), and rotation air help supercell thunderstorms form, but just the right temperature gradient and movement of air need to be present for a tornado to form. Quintessentially in the Midwest and Southern states, the convergence of cold, dry air from the northwest (the Rockies) and warm, moist air from the southeast (the Gulf of Mexico) sets up the stage for tornado formation.

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Formation of a Tornado

Compared to hurricanes, tornadoes cover less surface area (usually about 76 meters in diameter), travel fewer miles, are shorter-lived, and are colossally more unpredictable. Although most tornadoes last for under ten minutes, larger tornadoes can last around 30 minutes. According to the relatively new Enhanced Fujita Scale (adopted in 2007), a tornado must have at least wind speeds of 65 mph to be considered an EF-0, and any wind speeds above 200 mph would classify the tornado as an EF-5.

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Enhanced Fujita Scale

Tornado season typically lasts from March to May in the Southern states, May to early June in the Southern Plains, and June to July in the Northern states and upper Midwest. Given the right conditions, a tornado can develop in any place in the United States, whether over land or water (over water, they are called waterspouts). In fact, there was a tornado last week that touched down Scandia, PA (not too far from State College), an atypical location for a tornado. We hear about record-setting, deadly tornadoes happening in Tornado Alley, but personally, I find the more rare tornadoes to be most profound and intriguing.

On July 21, 1987, an extremely rare high-altitude tornado cut through a 24-mile long and 1.5-mile strip of land, crossed the Teton Wilderness and Yellowstone National Park, and even made it across the Continental Divide at elevations ranging from 8,500 to 10,000 feet! More impressively, it was an F4 tornado (207-260 mph winds), the strongest ever recorded in the state of Wyoming! Essentially, it was the result of a low pressure system which extended a cold front to the southwest and remarkably high temperatures at high elevations.

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Surface Map at 1700 MST (00Z) on July 21, 1987

As expected in such a sparsely populated area, there were no recorded human deaths or injuries; however, up to one million trees were uprooted by the tornado, leaving an appalling landscape. While it was not the highest-altitude tornado (the record belongs to a tornado in Sequoia National Park on July 7, 2004 at 12,000 feet altitude), the sheer power of the storm at an unusual location makes it so fascinating.

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Aerial Photograph of the F4 Damage

The Teton-Yellowstone tornado did not only defy the odds, but it also served as reminder that severe weather can occur anywhere with the right conditions. It is essential that people are informed of the latest and most accurate weather information because tornadoes have and can occur near you. As a severe weather enthusiast, I am blown away by the magnificence and potency of tornadoes. Tornadoes can cause mass devastation and fatalities, but I hope that you can see the beauty in it. Just make sure you don’t get literally blown away!

 

3 thoughts on “Teton-Yellowstone Tornado”

  1. I really like the topic that you chose for you blogs; tornados are really interesting phenomena that I really didn’t understand that fully previously. I definitely still had the Wizard of Oz perspective of a tornado! I think your post becomes a lot more relatable to most people when you talk about how tornadoes can really occur anywhere, as opposed to only in Tornado Valley, where the majority of tornadoes occur. I appreciate how you included the images to show how tornadoes form and can be classified in intensity. It helps me and other readers to get a better idea of them. It is fascinating how a tornado can come about as strong as one did in Yellowstone and Tetons National Parks. With all the recent focus on deforestation and destruction of wilderness by man, it provides a reminder that trees can be uprooted by the wilderness itself, wreaking as much havoc as any person could. I also love your pun at that end “don’t get literally blown away.” Very clever!

  2. The state of Utah had the same thing happen on August 11, 1993 and again on the same date of 1999. The first was a high altitude tornado that occurred in the high Uintas, a mountain range that runs East and West along the North-East border of the state. It was rated as an EF-3 and to this date is still the largest tornado to hit the state. It is rare for Utah to get tornados at all, but even more rare to hit a mountain range at 10,000-11,000 feet. The second d occurred exactly 6 years later, and hit down-town Salt Lake City. That was also rare in that it was the most destructive tornado the state has ever had, it occurred in the intermountain west region, and it hit a down-town densely populated area. That pretty much debunks every myth out there about tornados…they really can occur any where. Thanks for the read!

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