Update 11:30 p.m.

The flash flood warning for Oahu has expired.

9:30 p.m.

Landslides in east Maui have triggered road closures, the Maui Police Department announced this evening.

Piilani Highway at mile markers 36-37, in the Kaupo area, is closed, and the closure is expected to last until at least Friday morning. Road closure signs have been posted at mile marker 46 and in Ulupalakua.

Meanwhile, a landslide at Hana Highway at mile marker 11.5 is blocking the Hana-bound lane. State highway personnel are en route to the scene.

8:45 p.m.

The National Weather Service in Honolulu has issued a flash flood warning for Oahu until 11:30 tonight.

Radar this evening indicated heavy rain over the Koolau range with the heaviest rain falling over the slopes from Heeia to Kaaawa. Rain was falling at a rate of 1 to 2 inches per hour.

The Waiahole Stream has risen rapidly in response to the rain and the Waihee Stream gage remains elevated. Flash flooding is ongoing or expected to begin shortly in the area.

Some locations that will experience flash flooding include Waikane, Waiahole, Mililani, Wahiawa, Kahaluu, Pearl City, Ahuimanu, Aiea, Halawa, Moanalua, Kaneohe, Kalihi, Haleiwa, Maunawili, Manoa, Kailua, Waimanalo, Kahana Valley State Park, Whitmore Village and Helemano Housing.

7:45 p.m.

A flood advisory has been issued for Oahu until 10:45 tonight.

Radar this evening indicated heavy rain falling at a rate of 1 to 2 inches per hour over the Koolau mountains. Stream levels in the area will remain elevated from the rain.

Some locations that will may flooding include Waikane, Waiahole, Mililani, Wahiawa, Kahaluu, Pearl City, Ahuimanu, Aiea, Halawa, Moanalua, Kaneohe, Kalihi, Haleiwa, Maunawili, Manoa, Kailua, Waimanalo, Kahana Valley State Park, Whitmore Village and Helemano Housing.

Previous coverage

The National Weather Service today issued flood advisories for Maui and the Big Island.

Maui’s advisory was in effect until 6:15 p.m., while Hawaii island’s advisory expired at 6:45 p.m.

At 3:01 p.m., radar data indicated heavy rain over windward east Maui, while the stream gauge at Oheo Gulch has been rising. Rain was falling at a rate of 1 inch per hour and additional rainfall is expected through the evening.

Some locations that will experience flooding include Kipahulu, Kaupo, Nahiku, Hana, Keanae, Haleakala National Park, Wailua and Hamo, forecasters said.

Radar also indicated moderate to heavy rain falling on the island of Hawaii at 3:45 p.m. Rain was falling at a rate of up to 1.5 inches per hour over Hilo and Puna, and showers are expected to continue through tonight.

On the Big Island, some areas that will see flooding include Hilo, Hawaiian Paradise Park, Mountain View, Hawaiian Acres, Glenwood, Orchidlands Estates, Keaau, Pahoa, Volcano, Papaikou, Hawaii Volcanoes National Park, Pepeekeo, Honomu, Hakalau, Ninole, Kurtistown, Fern Acres, Eden Roc and Fern Forest.

Weather officials urge residents to stay away from streams, drainage ditches and low lying areas that are prone to flooding.

Both advisories may be extended if flooding persists.

A winter weather advisory was also issued for the Big Island today and remains in effect from 6 p.m. to noon Friday.

Big Island summits are expected to see snow accumulation of about 2 inches with a chance of freezing rain.

Residents should be prepared for slippery roads and limited visibility in affected areas.

Meanwhile, a brown water advisory has been issued on Oahu as a result of stormwater runoff entering coastal waters due to heavy rain.

The Hawaii Department of Health is advising the public to stay out of flood waters and stormwater runoff due to the potential for overflowing cesspools, animal fecal matter, pathogens and other contaminants associated with flood debris.

“Not all coastal areas may be impacted by runoff, however, if the water is brown stay out,” health officials said in an email. “Continue to practice good personal hygiene and follow-up with your primary care physician if you have any health concerns.”