1987 Teton–Yellowstone tornado

1987 F4 tornado in Wyoming, United States February 2023 August 2019 Teton–Yellowstone tornado 1987 Teton Wilderness tornado tree damage.jpg A large swath of trees leveled by the tornado July 21, 1987 July 21, 1987, 1:28 p.m. MDT (UTC−05:00) 26 minutes July 21, 1987, 1:54 p.m. MDT (UTC−05:00) F4 207-260 mph km/h on 1987 None 2500000 Teton Wilderness, Yellowstone National Park tornado outbreaks of 1987 The Teton–Yellowstone tornado was a rare high-altitude tornado which occurred on July 21, 1987, in the U.S. state of Wyoming.Fujita T. Theodore Ted Fujita 1989-09-01 The Teton-Yellowstone Tornado of 21 July 1987 Monthly Weather Review 117 9 1913–1940 1989MWRv..117.1913F 10.1175/1520-0493(1989)117<1913:TTYTOJ>2.0.CO;2 1520-0493 American Meteorological Society freehttp://www.spc.noaa.gov/faq/tornado/ The Online Tornado FAQ Edwards Roger Roger Edwards (meteorologist) January 29, 2009 National Weather Service December 21, 2009 March 2, 2012 https://web.archive.org/web/20120302230203/http://www.spc.noaa.gov/faq/tornado/ live Rated at F4 on the Fujita scale, it remains the strongest tornado ever recorded in the state and the only officially rated F4/EF4 in Wyoming history.Wyoming Climate Atlas http://www.wrds.uwyo.edu/sco/climateatlas/severe_weather.html https://web.archive.org/web/20221019050119/http://www.wrds.uwyo.edu/sco/climateatlas/severe_weather.html October 19, 2022 December 21, 2009 Water Resources Data System & State Climate Office Wyoming State Climate Officehttp://www.tornadohistoryproject.com/ Tornado History Project: Maps and Statistics January 7, 2014 January 17, 2018 https://web.archive.org/web/20180117024312/http://www.tornadohistoryproject.com/ usurped The tornado cut through a 39.2 km mi on flip-long and 2.5 km mi on flip-wide swath of the Teton Wilderness and Yellowstone National Park, crossing the Continental Divide. Damage occurred at elevations ranging from 8500 to 10000 ft m, making it the highest-altitude violent tornado recorded in the United States. At the time, it was the highest-elevation tornado known,Thuermer Jr. Angus M. August 5, 1987 Storm was world-record tornado 1, 12 Jackson Hole News https://www.newspapers.com/clip/117585285/storm-was-world-record-tornado-page-1/ January 30, 2023 Newspapers.com January 30, 2023 https://web.archive.org/web/20230130181859/https://www.newspapers.com/clip/117585285/storm-was-world-record-tornado-page-1/ live since surpassed by several others, including a 2004 tornado above 12000 ft m in California's Sequoia National Park.Monteverdi John P. Edwards Roger Stumpf Gregory J. 2014-11-01 An Analysis of the 7 July 2004 Rockwell Pass, California, Tornado: Highest-Elevation Tornado Documented in the United States Monthly Weather Review EN 142 11 3925–3943 10.1175/MWR-D-14-00222.1 2014MWRv..142.3925M 120568073 1520-0493 free While no human fatalities or injuries occurred, an estimated one million trees were felled by the tornado.Tornado Information http://www.crh.noaa.gov/riw/severe/tornado.php dead https://web.archive.org/web/20061004105837/http://www.crh.noaa.gov/riw/severe/tornado.php October 4, 2006 December 21, 2009 National Weather Service Weather Forecast Office, Riverton, WY NOAA The tornado damage was originally thought to be the result of strong thunderstorm straight-line winds until the area was surveyed by University of Chicago severe weather meteorologist Ted Fujita and his colleagues, who published a paper in 1989 surveying the tornado's path and discussing its meteorological character. Meteorological synopsis The tornado developed on July 21, 1987, from a severe thunderstorm that produced a mesocyclone near the intersection of a mesohigh boundary and a warm front. The parent storm was tracked using infrared satellite imagery from GOES satellites. The storm moved at approximately 25 m/s (90 km/h; 56 mph), while satellite imagery showed a pronounced increase in very cold cloud-top temperatures during the tornado's development.Fujita T. Theodore The Teton-Yellowstone Tornado of 21 July 1987 Monthly Weather Review 117 9 1913–1940 1989 10.1175/1520-0493(1989)117<1913:TTYTOJ>2.0.CO;2 The tornado formed at approximately 1:28 p.m. MDT and initially produced relatively weak tree damage. It intensified rapidly near Gravel Ridge, where a small area of extreme forest damage was rated F4 on the Fujita scale. The tornado subsequently produced extensive F2 and F3 damage as it traveled through the mountainous terrain of the Teton Wilderness. The tornado crossed the Continental Divide at approximately 3,070 m (10,070 ft) above sea level. Fujita's aerial survey documented a damage path approximately 39.2 km (24.4 mi) long and 2.5 km (1.6 mi) wide. The survey also identified four apparent spin-up swirl marks and 72 microburst outflows within the broader damage area. The tornado continued eastward toward the Yellowstone River valley before dissipating at approximately 1:54 p.m. MDT. Fujita estimated that the tornado remained on the ground for approximately 26 minutes and had an average forward speed of about 25 m/s (90 km/h; 56 mph). Storm development and track The tornado track began in a valley 3 km mi flip to the northeast of Mount Randolph,1917 Fujita estimated the tornado first developed at 1:28 p.m. MDT.1933 The damage path became wider and more consistent as it approached Gravel Ridge, producing a large area of tree damage to the northeast of the ridge.1917 The tornado appeared to intensify quickly, as the damage it produced increased from F0 intensity to F4 intensity in less than 5 km mi flip, estimated at three minutes of travel time. The lone area of F4 damage was found north of Gravel Ridge,1923 based on a small area affected by the worst tree damage: large Engelmann spruce trees between 30–40 cm in in diameter were found uprooted and stripped of their bark, with the bare trunks spattered with wind-blown topsoil.1923 Meteorologist Ted Fujita noted that the only comparable forest damage he had seen associated with an F4 tornado had been in the Appalachian Mountains after the Murphy, North Carolina tornado of the 1974 Super Outbreak.1923 The tornado maintained F2–F3 intensity for the next 10 km mi flip, producing a large swath of tree damage. During this period, it approached and crossed directly over Enos Lake in the Bridger–Teton National Forest.1917 A group of nine campers near Enos Lake reported that they saw no funnel cloud, but that the storm developed quickly and a "roar like a train in the distance" was accompanied by hailstones the size of golf balls. Fujita hypothesized that because of the area's high elevation and the storm's low cloud base, no funnel cloud would have been visible.1926 The tornado then descended into Pacific Creek Valley before climbing up to a high plateau at nearly 3000 m ft flip in elevation, weakening significantly. It produced more tree damage on steep slopes until it crossed the Continental Divide, damaging trees at an elevation of 10070 ft m. More severe tree damage occurred in several cirques. The tornado then crossed the drainage of Falcon Creek before descending into the Yellowstone River Valley, gradually weakening as it did so. The damage path became more sporadic until it disappeared on the valley's far eastern side,1917 with the tornado's time of dissipation calculated to have been 1:54 p.m. MDT.1933 Summary thumb|right|Damage track map of the tornado through the Teton Wilderness and Yellowstone National Park The tornado's total damage path was 39.2 km mi flip long, with an average width of 2.5 km mi flip and a maximum width of 3.9 km mi flip.1916–1917 Fujita estimated the tornado's duration on the ground at approximately 26 minutes,1938 with a forward velocity of 90 km/h mph flip.1917 Aftermath No casualties resulted from the tornado, though as many as twelve people were trapped in the backcountry by the storm. Trail maintenance crews and other federal workers labored for weeks to clear approximately 15 miles of trail blocked by the downed trees, and the total cost of the damage was recorded as $2.5 million. Discovery and study After the July 23 report of a massive blowdown in the Teton Wilderness by the Forest Service, Fujita arranged for multiple aerial surveys by Cessna aircraft of the tornado's track, resulting in more than 1,400 photographs that recorded every single damaged tree. The southernmost area of the track was also visited on foot and photographed by Fujita's colleague Bradley S. Churchill. Timber blowdown In the fall of 1987, U.S. senator for Wyoming Malcolm Wallop, the Fremont County Commission, and timber groups lobbied for the ability to harvest the fallen timber from the tornado's path, arguing that it posed a threat because of wildfire and beetle infestation risks and would provide nearby lumber mills with work. The Wyoming Chapter of the Sierra Club opposed the suggestion on the grounds that the harvesting would require many miles of logging roads through wilderness and would create a dangerous precedent.September 1, 1987 The Wyoming chapter of the Sierra Club says it... United Press International https://www.upi.com/Archives/1987/09/01/The-Wyoming-chapter-of-the-Sierra-Club-says-it/4387557467200/ January 30, 2023 In the end, much of the area burned in the Huck Snake River Complex and Mink Creek fires during the Yellowstone fires of 1988. Though several thousand acres of the tornado blowdown track remained unaffected,Greater Yellowstone Coordinating Committee January 25, 1989 The Greater Yellowstone Fires of 1988: Questions and Answers http://npshistory.com/publications/yell/1988-fire-qa.pdf live https://web.archive.org/web/20221224094629/http://npshistory.com/publications/yell/1988-fire-qa.pdf December 24, 2022 January 30, 2023 NPS History Electronic Library & Archive it prevented Fujita and his colleagues from returning to perform follow-up aerial photographic surveys and site visits.1938–1939 See also 2009 Goshen County tornado - A strong EF2 tornado in Goshen County, Wyoming that was well documented References 2 44.02 N 110.23 W title Category:Meteorological events in 1987 Category:Climate of the Rocky Mountains 1987-07-21 07-21 1987-07-21 Category:Teton County, Wyoming Category:Yellowstone National Park Category:July 1987 in the United States