Manoa, Kane'ohe, Kailua and Waimanalo were drenched by the storm, which dumped 4 to 6 inches of rain an hour over the Ko'olau range, said Bob Farrell, the National Weather Service's lead forecaster.

Merchants and residents alike felt the wrath of the rain.

"We have big-time flooding," said Marlene Kanca, manager of the Longs drugstore at 2750 Woodlawn Drive, in Manoa Marketplace. "There are cars floating away on Woodlawn Drive. We've called 911."

Many of those cars belonged to shopping center employees, Kanca said.

The American Red Cross opened a shelter at the Manoa Valley District Park, anticipating that about 30 people needed shelter after their homes were flooded, said Cassandra Isidro, Red Cross chief operating officer.

Manoa was the area hardest hit. The flash flood left behind mud-covered streets and homes. Streets were littered with trash from dislodged garbage cans. Tree limbs and roots clung to the railing of the bridge on East Manoa Road that crossed Manoa Stream. A backhoe was needed to remove debris from Huelani Drive in Manoa, leaving about 30 homeowners with no way out of their street.

About three cars were still missing late last night, most of them from the Woodlawn Drive area. People abandoned their cars in the middle of intersections during the downpour. But by 10:30 last night, the rain had tapered off and the seven fire companies that had responded were back at their stations, said Fire Battalion Chief James Arciero.

"It was like someone took a sponge and hung it over Manoa and squeezed it," Arciero said.

By that time, residents could come out of their homes and assess the damage. For some, it meant just a hose to wash away the layer of mud. But for others, like Eileen Saito, the job at hand was overwhelming.

A layer of mud coated the floor and soaked through boxes of medical supplies in Saito's studio apartment on East Manoa Road. Nothing was spared. Not her bedding, clothes, medical supplies or even her dog, who sat shivering in a plastic box.

A kind neighbor lent her a set of dry clothes because her just-cleaned laundry was colored mud-brown and sopping wet.

"It was knee-deep," Saito said. "I had no chance to get things packed up. Mud was backing up in the toilet.

"Look at our house. Look at our dog. Now, where are we going to sleep?"

The flooding left several streets closed last night in Manoa, but many reopened.

There will be more rain today, but not nearly as heavy as last night, where one rain gauge reported 1.03 inches in a 15-minute period in Kane'ohe, Farrell said.

A flood warning was issued for Kane'ohe, Kailua, Waimanalo and Manoa.

"We're looking for better weather for Halloween," said Farrell, indicating that all the "main action" took place last night.

Many of the calls for firefighters were for help in flooded homes and to rescue stranded motorists, said Honolulu Fire Capt. Emmit Kane.

The weather service had expected the storm but didn't know it would produce such a deluge on O'ahu, Farrell said.

The heavy rain affected Likelike and Pali highways as well as Nu'uanu and Kalihi valleys, Farrell said.