Thousands of people stepped around puddles and returned to soggy Oahu beaches Sunday after a storm delivered thunder and lightning and triggered flooding from Kahaluu to Punaluu, clogging traffic along Windward Oahu.

Weather forecasters say the worst is likely over, but another weather system could move back over the islands on Wednesday.

Despite warnings of sewage spills and storm runoff, people lined Oahu beaches from Haleiwa to Waimanalo on Sunday as sunny skies returned.

The state Health Department issued a brown-water advisory for waters from Waikane to Haleiwa Beach Park because of possible overflowing cesspools, sewer manholes, pesticides, animal fecal matter, dead animals, flood debris and other chemicals and bacteria that may have been washed into the ocean by the heavy rain.

If the water is turbid and brown, the Health Department advises swimmers to stay on land.

A large funnel cloud was spotted at 11:25 a.m. Sunday north of Waipahu, but it didn’t touch down.

Saturday’s storm delivered an estimated 13,387 lightning strikes and dropped several inches of snow on Mauna Kea and Mauna Loa, a relatively rare sight in June.

Park rangers reported up to 8 inches of snow on the road leading to the summit of Mauna Kea, the National Weather Service said.

At 8:46 p.m. Saturday, rain was falling at a rate of about 4 inches an hour around Oahu, the National Weather Service said.

"There was a lot of water in a short period of time," said Honolulu Fire Capt. Robert Main.

Firefighters responded to 23 calls between 7:30 and 11:23 p.m. and had to prioritize their response because of the volume of 911 calls throughout Windward Oahu.

Three adults and two children were stranded when their vehicle stalled while crossing floodwaters on Kamehameha Highway, Main said.

A mother and child made it to the Kahaluu side of the highway, but the three others in the vehicle were trapped and climbed onto the roof of the vehicle. Firefighters assisted them in getting to the Waikane side of the stream, helped them dry out and eventually reunited the family, Main said.

About 7,700 Hawaiian Electric customers were without power in Kaneohe from 9 p.m. Saturday until midnight, and there were smaller outages in Kailua, Punaluu and Pearl City until around 3 a.m. Sunday, the company said.