KAILUA-KONA — Heavy rains in Kona and the rest of the island resulted in a flash flood warning for most of Tuesday and a brown water advisory expected to remain in place in the coming days.
While the warning — in effect for the entire island throughout the morning Tuesday — was lifted for Kona by afternoon and the entire island shortly thereafter, a flash flood watch issued by the National Weather Service remained in effect into the night.
Around 7:15 a.m., radar showed heavy rain over parts of the island, with the heaviest rainfall in Kona and Kohala from Kealakekua to Hawi. Rain was also falling on eastern slopes from Pahala to Honomu.
Rain was falling at a peak rate of 1-2 inches per hour.
Even as Tuesday’s rain continued to lightly fall on those strolling up and down Alii Drive during the evening, Kentucky residents Mike and Debbie Kennedy said the weather wasn’t ruining their vacation to Kona.
“We didn’t expect it,” said Mike Kennedy, “because …”
“It’s been so beautiful,” Debbie Kennedy said.
In fact, Mike Kennedy said, it actually gave them a break from the tours and sightseeing they’ve been doing. And they were still able to take a helicopter ride over the northern part of the island.
“It was cloudy,” he said. “But we got under the clouds, and it was really an enjoyable experience.”
The heavy rain earlier Tuesday resulted in ponding on roadways and led to the closure of Kuakini Highway from Hillside Plaza to Walua Road in Kailua-Kona.
Police also saw an increased number of vehicle crashes Tuesday compared to a typical day. Hawaii Police Department Maj. Robert Wagner said police responded to a total of seven crashes, compared to about five throughout a given day. Five of the day’s crashes were reported before 11 a.m.
None of the day’s crashes resulted in serious injuries.
Shortly before 1:15 p.m., radar and data indicated that rain fall had ceased over most of the island except for a band that continued to affect part of the Puna District.
In that same notice, the Weather Service said that Hawaii County Civil Defense reported that flooding issues had subsided in most of Kona and Ka‘u.
As runoff from the day’s storms flowed into coastal waters, the state’s Department of Health Clean Water Branch issued a brown water advisory for the entire island.
The brown water advisory means the public is advised to avoid runoff from the storms because of potential sewage from overflowing cesspools or sewers as well as contaminants from pesticides, dead animals, pathogens and other flood debris.
“All those things can be flushed into the ocean from the land,” said Myron Honda, environmental health specialist for the Clean Water Branch.
And given the murky waters, Honda added, there’s also a possibility of sharks.
“That’s probably the best reason to stay out,” he said.
Honda added that depending on the soil in a given area, water might not actually appear brown, but could still contain contaminants.
Generally, Honda said, advisories stay up two to three days after the last rainfall event. That gives time for the contaminants to move out of the waters closest to the coastal areas.
“It’ll be up for a couple days at least,” Honda said.
The harsh weather might not be over.
The potential for heavy rain and thunderstorms remained over the night, National Weather Service Meteorologist Leigh Anne Eaton said, and there was still some moisture expected to be stalled out over the island through Thursday.
While that can still bring some rain, she said, it’s not going to be as intense as what’s been seen.
“It should be improving from here on out pretty much,” she said.
Trade winds are expected to return Thursday evening.
Eaton said that between 3 p.m. Monday and 3 p.m. Tuesday, 1.44 inches of rain was recorded as having fallen at the Ellison Onizuka Kona International Airport at Keahole. More than four times that — 6.75 inches of rain — was recorded during the same time frame at the Hilo International Airport.
As a result of the weather conditions, about 4,600 Hawaii Island customers were reported as having experienced power interruptions.
Hawaii Electric Light Co. said that as of early Tuesday afternoon, about 250 customers were without power in Kailua-Kona, lower Puna, Volcano, Ka‘u and the Hamakua Coast.