The National Weather Service has issued a flood advisory for South Hilo, Puna and Ka‘u.
A flood advisory means flooding is imminent or already occurring.
A strong winter low-pressure system passing to the north of the state will drag a strong cold front from northwest to southeast down the island chain tonight and Friday. Heavy rainfall and thunderstorms developing along and ahead of the front will bring the potential for flash flooding.
The entire state, including the remainder of the Big Island, is under a flood watch until 6 p.m. Friday, and the Big Island is under a high wind warning until noon Friday.
In addition, a winter storm warning is in effect for the summits and upper slopes of Maunakea and Mauna Loa.
“The heaviest rain looks like it’s going to be late tonight, early morning,” John Feerick, Accuweather senior meteorologist said today. “We’re probably talking about some flooding issues. I’d certainly expect that we’re going to see some places that are going to get 2 to 4 inches of rain. If you go up in elevation, it’ll probably be a little bit more than that.
“It’s definitely going to be a significant rainstorm for the Big Island.”
Feerick said the heaviest showers likely will be in West Hawaii, “but the entire island should be battening down the hatches.”
A thunderstorm struck East Hawaii early this morning. Hilo International Airport recorded just over an inch of rain in the 24 hours ending at 8 a.m. today, while Kapapala Ranch in Ka‘u measured 1.23 inches.
The heaviest rainfall was reported at Keaumo, on the southeastern slope of Mauna Loa, with just under 3 inches.
There were early afternoon power outages reported in downtown and midtown Hilo, as well as Papaikou, and Hawaiian Electric posted an advisory on its Facebook page at 1:30 p.m.
“We urge customers to prepare for the possibility of extended power outages due to a powerful storm system that is moving across the state,” the post states. “Outages are being reported on all islands as strong winds and thunderstorms began early this morning. The number of customers and impacted areas are dynamic and will change as the storm makes its way across the island chain.”
“Our crews are currently responding to outages, and we want to reassure our customers that we’re on the job, ready for the impacts of this storm system,” said Jim Alberts, senior vice president and chief operations officer. “In the past 24 hours, we’ve increased our restoration team and have workers standing by to restore power as quickly as possible. As long as it’s safe, we’ll work continuously after the storm clears until all customers have power again.”
The county Department of Water Supply is urging customers to prepare for possible interruptions to the electrical utility and subsequently their water service that could result from the storm system.
“DWS requires a significant amount of dependable electricity to deliver an adequate and continuous supply of safe drinking water to all customers. Much of this electricity is supplied by Hawaiian Electric, which is directing its customers to prepare for possible power outages,” DWS said in a statement.
Mayor Kimo Alameda signed an emergency proclamation today in anticipation of severe weather across Hawaii Island. The proclamation allows the county to streamline its response and coordinate resources as heavy rainfall and high winds are expected.
“We urge our residents to stay prepared and take extra precaution as severe weather moves across the island,” Alameda said. “Crews are working hard to ensure roadways are clear and to restore power to traffic intersections. We ask residents to remain off roadways if possible as weather conditions worsen and to stay connected to our emergency notifications.”
The county announced that several shelters opened today in anticipation of severe weather.
Seven emergency shelters are currently open, with a total of 11 available. Additional shelters will be opened and staffed as needed.
Thoese open include: Waimea Community Center; Naalehu Community Center; Robert N. Herkes Gym in Pahala; Yano Hall in Captain Cook; Kekuaokalani Gym in Kailua-Kona; Keaau Armory and Pahoa Neighborhood Facility.
The following facilities are closed due to storm impacts: Mahukona Wharf; Carvalho Park; Panaewa Rainforest Zoo and Gardens; Keaau Armory, which is closed for normal daily activities but remains open as a shelter; and Pahoa Pool.
In addition, all county campsites are closed until further notice to ensure public safety.
Email John Burnett at jburnett@hawaiitribune-herald.com.