Darby weakened to a tropical depression overnight, leaving a muddy mess behind on Oahu.

The National Weather Service lifted a flash flood watch for Oahu and Kauai as the storm continued on a path to the northwest of the main Hawaiian islands. But the muggy conditions could still generate afternoon showers, forecasters said.

Cleanup of flooding on the H-1 freeway near School Street and on Dillingham Boulevard near Middle Street created heavy traffic for commuters this morning because of lane closures.

Red Cross volunteers are canvassing the hardest hit areas to assess the damage.

The Health Department issued a number of brown water advisories urging people to stay out of storm runoff in the ocean around Oahu and several other locations.

At estimated 1,200 gallons of wastewater spilled into the street and down a storm drain in Waolani Stream at Wyllie Street in Liliha. Signs are posted along the stream to Honolulu Harbor.

More than 1,000 gallons of sewage spilled out of two manholes at Atkinson Drive and Ala Moana Boulevard near Ala Moana Center Sunday night.

Another brown water advisory was issued for Heeia Fishpond after Heeia Stream overflowed and flooded the Punawai Pump Station, sending about 600 gallons of wastewater from a manhole into Heeia Fishpond.

People are being warned not to go into the water around Oahu because of murky, brown water conditions. The Health Department said storm runoff contains pollution and fecal matter that could be a health hazard. The murky water can also attract sharks.

Warnings are also posted around Hanalei Bay on Kauai and Hilo Bay on Hawaii island because of heavy rain runoff.

Packing maximum sustained winds of 35 mph as of 11 a.m. this morning, Darby was about 210 miles west-northwest of Honolulu and moving west-northwest at 9 mph.

Forecasters expect Darby to continue weakening over the next two days, possibly becoming a post-tropical low Tuesday.

As rains eased this morning, the city closed seven evacuation centers set up to shelter people from the storm.

The American Red Cross reported that 233 people stayed overnight. There were 199 people at the BYU-Hawaii shelter, including students from France who were camping at Malaekahana Beach Park this weekend. Another 18 people stayed at Waimanalo District Park shelter, and 16 people stayed at the McKinley High School shelter.

Over 10 inches of rain fell in Luluku, Kaneohe, upper Nuuanu and Moanalua over the 24-hour period ending at 5 a.m., according to rain gauges.

At Honolulu Airport, the 1.47 inches recorded Sunday broke the rainfall record for that day, set in 1986 at .66 inches.

Police closed the H-1 westbound at the School Street off-ramp last night around 11:37 p.m. after heavy rain and ponding created dangerous driving conditions. Some freeway lanes reopened shortly after 5:30 a.m., but the Dillingham Boulevard and Middle Street off-ramps remain closed after mud and debris washed over the roadway overnight.

Customers, mostly in town and East Oahu, experienced power outages Sunday night due to the storm conditions, according to reports online.

Hawaiian Electric reported there were pockets of outages reported throughout Sunday night with only 400 customers without electricity at 7 a.m. in town and Windward Oahu.

“Crews were working throughout the night to restore power when outages were reported,” said Darren Pai, HECO spokesman.

Hawaiian Electric asks people who see downed power lines to call their trouble line at 1-855-304-1212.