Hawaiʻi Mesonet captures 135 mph winds, extreme rainfall during storm

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From 135 mph wind gusts on Hawaiʻi Island to 62 inches of rainfall on Maui, a recent Kona low system brought weather conditions usually reserved for major hurricanes to the state. These extreme totals were captured by the University of Hawaiʻi's Hawaiʻi Mesonet, a weather monitoring system that is mapping localized threats across areas that previously had no data available. UH's Hawaiʻi Climate Data Portal team created a report on the storm.

Alongside immense flooding, the storm brought destructive winds. The Hawaiʻi Mesonet station at Kaiāulu Puʻuwaʻawaʻa on Hawaiʻi Island recorded a maximum wind gust of 135.4 mph. Winds were briefly sustained at speeds equivalent to a Category 2 hurricane, averaging 105 mph over a 15-minute period.

Maui was hit the hardest, with peak rainfall totals reaching 62 inches in localized regions. Hawaiʻi Island also saw heavy precipitation, with areas recording 16-32 inches, and isolated spots also nearing 62 inches. Both Kauaʻi and Oʻahu recorded maximum totals ranging 16-32 inches. Molokaʻi and Lānaʻi experienced peak amounts 4-16 inches.

The upper elevations of Haleakalā experienced the most extreme rainfall, with 33 inches falling during the 24-hr period beginning March 13 at 8:30 a.m., nearly double the highest 24-hr rainfall previously recorded there. That amount is much greater than the National Oceanic and Atmospheric Administration's official estimate of 19.7 inches in 24 hours for the 1000-year storm (the rainfall amount with a 0.1% chance of being equalled or exceeded in any given year). Rainfall was even higher at the Kuiki Hawaiʻi Mesonet station on the east rim of Haleakalā crater with 36 inches falling in 24 hours beginning at 6 p.m. on March 13. This amount exceeded the NOAA 24-hr 1000-year extreme rainfall estimate of 28.5 inches.

"Before the project began, Hawaiʻi was one of only 20 states without a comprehensive statewide weather monitoring system, meaning we previously had no access to information in many of these areas," said Tom Giambelluca, Hawaiʻi Mesonet project lead, and former director of the UH Water Resources Research Center. "Now, the system is constantly collecting data on rainfall, soil moisture, and other weather variables that can tell us in real time if an area is highly susceptible to fires or flooding, which ultimately allows us to be as prepared as possible"

To make this information accessible, UH launched a real-time weather dashboard offering public access to live weather data from more than 70 monitoring stations currently active across the state. The dashboard updates data every 15 minutes, allowing users to view current, localized conditions including temperature, rainfall, wind, humidity, solar radiation and soil moisture. This creates one of the most comprehensive and timely weather resources available in Hawaiʻi.