Severe thunderstorms packing torrential rain and even hail walloped areas of the Big Island on Monday as a strong cold front moved over the Aloha State.
West and North Hawaii took the brunt of the storm, it appears, with reports of hail up to ½ inch in diameter falling in South Kohala and Ka‘u as the most intense thunderstorms moved over the island Monday. Power outages, road closures prompted by flooding and downed trees also impacted residents from North Kohala to Ka‘u.
“It looks like Maui and the Big Island got a decent hit from this today,” said William Thomas, a forecaster with the Honolulu-based National Weather Service.
Twelve-hour rainfall totals were telling with some areas recording during that time period more than the average rainfall typically seen for all of December.
Kona International Airport saw 1.41 inches of rain between 4:45 a.m. and 4:45 p.m., well over the average 1.06 inches of rain the typically dry area sees during the 31 days of the final month of the year. Also topping monthly rain totals in the 12-hour period were Kaupulehu with 1.9 inches, Waikoloa with 1.7 inches, Kealakekua with 3.06 inches and Honaunau with 3.11 inches.
The highest 12-hour rainfall total was recorded by a rain gauge along Kawainui Stream on the wet side of Waimea with 6.18 inches, more than half of what’s typically seen in all of December for the area. Closer to Waimea’s town center, 3.28 inches fell.
The rainfall also prompted Hawaii County officials to cancel all remaining Hele-On routes for the day shortly before 7:30 p.m. Shelters were also opened Monday evening at Old Kona Airport in Kailua-Kona and Waimea Community Center in Waimea as the severe weather continued to impact residents. The shelters will remain open until further notice.
In East Hawaii, rainfall totals were far less with Hilo Airport seeing less than a half-inch of rain during the 12-hour period. Honokaa reported just under ¾ of an inch while Pahala reported zero rainfall.
Forecasters said the threat of flash flooding and severe thunderstorms remained possible overnight into Tuesday as the last of the vigorous cold front moved east and away from the Big Island.
Conditions are forecast to improve Tuesday, and by Wednesday, winds will become light and fair weather should return.
“It should be clearing out,” said Thomas. “Tomorrow should be a lot better than today.”
By the end of the week, another cold front is forecast to move into the area. The current forecast track has the front staying north of the state, resulting in showers mainly over Kauai and Maui.