{"id":158056,"date":"2022-04-26T08:00:24","date_gmt":"2022-04-26T18:00:24","guid":{"rendered":"https:\/\/www.hawaii.edu\/news\/?p=158056"},"modified":"2022-06-17T12:42:44","modified_gmt":"2022-06-17T22:42:44","slug":"supercell-thunderstorms-kauai-rain","status":"publish","type":"post","link":"https:\/\/www.hawaii.edu\/news\/2022\/04\/26\/supercell-thunderstorms-kauai-rain\/","title":{"rendered":"Supercell thunderstorms caused Kaua\u02bbi\u2019s record rainfall in 2018"},"content":{"rendered":"Reading time: <\/span> 2<\/span> minutes<\/span><\/span>
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Kauaʻi’s<\/span> record-setting rain flooded areas and damaged homes.<\/figcaption><\/figure>\n

A record-setting rainstorm over Kauaʻi<\/span> in April 2018 resulted in severe flash flooding and estimated<\/a> damage of nearly $180 million. The deluge damaged or destroyed 532 homes, and landslides left people along Kauaʻi\u2019s<\/span> north coast without access to their homes for months. In a published study<\/a>, atmospheric scientists at the University of Â鶹´«Ã½<\/span> at Mānoa revealed that severe supercell thunderstorms were to blame.<\/p>\n

The rainstorm inundated some areas with nearly 50 inches of rainfall in a 24-hour period, smashing the previous 24-hour U.S. rainfall record of 42 inches set in Texas in 1979. An interesting finding is that the rainstorm described in this paper was associated with a Kona low and not a tropical cyclone as featured in previous U.S. rainfall records.<\/p>\n

Terrence Corrigan<\/strong>, a doctoral candidate, and professor Steven Businger<\/strong>, both in the Department of Atmospheric Sciences<\/a> at the UH<\/abbr> Mānoa School of Ocean and Earth Science and Technology<\/a>, sifted through copious weather radar data from National Oceanic and Atmospheric Administration\u2019s National Weather Service to unveil the factors contributing to this historic event. Their analysis revealed large changes in the direction and speed of the winds in the lower atmosphere. When these shifting winds collided with Kauaʻi<\/span> steep cliffs, thunderstorms with rotating updrafts were triggered. The scale of rotation seen in radar data, and the strength of rainfall seen as reflectivity echos are consistent with supercell thunderstorms.<\/p>\n

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Waipā Garden rain gauge, northern slopes of Mount Waiʻaleʻale<\/span> in the background.<\/figcaption><\/figure>\n

“This finding was a surprise, which has interesting implications for other mountainous areas of the world,” said Businger.<\/p>\n

“Updrafts with rotation are more intense and longer lived, and have been observed to produce large hail and tornadoes in Â鶹´«Ã½,<\/span>” said Businger. “In this case, the updrafts were forced by Kauaʻi\u2019s<\/span> steep mountain cliffs, with the result that the thunderstorms were more vigorous and anchored to the terrain, thus setting a new U.S. 24-hour rainfall record!”<\/p>\n

Although supercell thunderstorms are the least common type of thunderstorm in Â鶹´«Ã½,<\/span> they have the greatest likelihood of producing severe weather, including large hail, tornados and strong straight-line winds.<\/p>\n

“Understanding the dynamic interaction of our tropical atmosphere and steep mountains will help weather forecasters better anticipate severe weather events and flash floods in our state and elsewhere,” added Businger.<\/p>\n

Businger and Corrigan\u2019s next steps are to use high resolution computer models to simulate the interaction between various wind flows and terrain configurations to further shed light on the interaction of mountains and severe thunderstorms.<\/p>\n

–By Marcie Grabowski<\/em><\/p>\n","protected":false},"excerpt":{"rendered":"

Supercell thunderstorms have the greatest likelihood of producing severe weather, including large hail, tornados and strong straight-line winds.<\/p>\n","protected":false},"author":16,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[30],"tags":[745,1467,1363,158,92,9],"class_list":["post-158056","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-research","tag-atmospheric-sciences","tag-manoa-excellence-in-research","tag-manoa-research","tag-publication","tag-school-of-ocean-and-earth-science-and-technology","tag-uh-manoa","entry","has-media"],"aioseo_notices":[],"jetpack_featured_media_url":"","_links":{"self":[{"href":"https:\/\/www.hawaii.edu\/news\/wp-json\/wp\/v2\/posts\/158056","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.hawaii.edu\/news\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.hawaii.edu\/news\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.hawaii.edu\/news\/wp-json\/wp\/v2\/users\/16"}],"replies":[{"embeddable":true,"href":"https:\/\/www.hawaii.edu\/news\/wp-json\/wp\/v2\/comments?post=158056"}],"version-history":[{"count":8,"href":"https:\/\/www.hawaii.edu\/news\/wp-json\/wp\/v2\/posts\/158056\/revisions"}],"predecessor-version":[{"id":160856,"href":"https:\/\/www.hawaii.edu\/news\/wp-json\/wp\/v2\/posts\/158056\/revisions\/160856"}],"wp:attachment":[{"href":"https:\/\/www.hawaii.edu\/news\/wp-json\/wp\/v2\/media?parent=158056"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.hawaii.edu\/news\/wp-json\/wp\/v2\/categories?post=158056"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.hawaii.edu\/news\/wp-json\/wp\/v2\/tags?post=158056"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}