Record-shattering rains trigger destructive floods in Hawaii, 699 mm (27 inches) in 24 hours

An upper level low west of Kauai and ample deep moisture have worked together to produce record-shattering rains in parts of Hawaii over the weekend. At least two homes were swept away by raging floodwaters and dozens more damaged. The hardest-hit area is between Hanalei and Haena. There are no reports of deaths or injuries at this time. 

Hawaii Governor David Ige issued an emergency proclamation for the island of Kauai on Sunday, April 15, 2018, after NWS gauges in Hanalei recorded record-shattering 699 mm (27.52 inches) of rain in a 24-hour period that ended 05:00 HST, April 15. Of the total amount, 213.3 mm (8.4 inches) fell between 11:00 HST on Saturday and 02:00 on Sunday.

"This beats all 1- and 2- day rainfall records at Hanalei," the NWS office in Honolulu said.

The previous 24-hour record for the island was 318 mm (12.52 inches), set in March 2012. During the same weather event, Hanalei recorded 609.6 mm (24 inches) in a 48-hour period and 838.2 mm (33 inches) in 72 hours. NWS records for the region date back to 1905.

The Hanalei River was at 4.49 m (14.76 feet) early Sunday morning, well above the 2.3 m (7.7 foot) flood stage.

Wainiha recorded 466.8 mm (18.38 inches) in a 24-hr period, Mount Waialeale 335.7 mm (13.22 inches) and Princeville Airport 246.6 mm (9.71 inches), with 159.5 mm (6.28 inches) falling between 03:00 and 07:00 HST, Sunday.

Island authorities sent first responders and helicopters to search for residents in need of rescue but they had to be grounded when heavy rainfall continued, Kauai County officials said.

At least two homes were destroyed and dozens were damaged or flooded in Hanalei, Wainiha, Haena, and Anahola, the county spokesperson said, adding that about 40 people are staying at the shelter in Hanalei.

The two homes destroyed were ripped from their foundations Saturday along Wainiha Powerhouse Road on the northern side of the island, local media reported. Officials believe they were vacant.

Image credit: Kresta Kay

Mudslides were reported on several major roads, including Kuhio Highway. The highway remains closed at several points.

Power and water outages are reported across the island.

The Hanalei Elementary school will be closed on Monday, county officials said.

Featured image: Home destroyed by flash floods in Hawaii on April 14, 2018. Credit: Kresta Kay