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<\/a>Honolulu Department of Emergency Management issued mandatory evacuations for communities in Waialua and Hale\u02bbiwa following heavy rainfall and flooding throughout O\u02bbahu during the second of back-to-back kona lows to hit the state from March 19-23. (Courtesy Photo: U.S. Coast Guard Air Station Barbers Point)<\/p>\nResearchers captured the scale of back-to-back kona low systems, mapping localized threats and providing crucial data about the state\u2019s severe flooding, using University of Hawai\u02bbi\u2019s Hawai\u02bbi Mesonet<\/a> and Hawai\u02bbi Climate Data Portal<\/a>.<\/p>\n Statewide rainfall averaged 18.25 inches from March 1-23 \u2014 more than 2.6 times the standard March average of 6.85 inches.<\/p>\n ARTICLE CONTINUES BELOW ADARTICLE CONTINUES BELOW AD<\/p>\n While the first storm from March 10\u201316 brought hurricane-force wind gusts of 135 mph to Hawai\u02bbi Island and up to 62 inches of rain on Maui, the second kona low from March 19-23 triggered a new wave of devastation, dumping up to 61 inches of rain in localized areas, producing destructive floods throughout eastern and central Moloka\u02bbi, West Maui and O\u02bbahu.<\/p>\n Communities such as Waialua and Hale\u02bbiwa on O\u02bbahu\u2019s North Shore experienced devastating inundation.<\/p>\n Hawai\u02bbi Mesonet stations highlighted the widespread intensity of the storm: the Ka\u02bbala station recorded the island\u2019s highest 2-day rainfall of roughly 22 inches, including 19.67 inches in a 24-hour period beginning the evening of March 19.<\/p>\n ARTICLE CONTINUES BELOW AD<\/p>\n Almost simultaneously, the nearby Kalahe\u02bbe Ridge station above Waimea Valley recorded 9.75 inches in 24 hours.<\/p>\n An intense, localized atmospheric event struck M\u0101noa and Palolo Valley on March 23 as the 2-week rainy period neared its end.<\/p>\n Honolulu Mayor Rick Blangiardi described it as a \u201cclassic rain bomb,\u201d heavy rain caused by a stationary storm cell. This \u201crain bomb,\u201d over M\u0101noa and Palolo Valley, dropped 2 to 4 inches of rain per hour.<\/p>\n ARTICLE CONTINUES BELOW AD<\/p>\n Six Hawai\u02bbi Mesonet stations in the Nu\u02bbuanu-M\u0101noa area recorded between 3.5 and 6.5 inches of rain, the majority of which fell within a 3-hour window. Falling on already saturated ground, this turned streams into raging torrents and triggered significant flash floods.<\/p>\n