Despite the torrential rain that pounded southern Maine on Wednesday night, Cherie Copeland had no idea that 3 feet of water had flooded the parking lot of the Portland hotel where she was staying until she emerged into the sunshine Thursday morning.

“When I came down to put the luggage in the car, the door clicker wouldn’t work,” she said.

She opened the trunk to find a puddle of water.

Copeland’s rental car was among dozens of vehicles damaged by flooding in the parking lot of the La Quinta Inns and Suites on Park Avenue, one of the low-lying areas hit hardest by floodwater that had nowhere else to go after a storm dropped record rainfall in Portland.

“This was a mighty storm,” said hotel guest Martin Spechler, as he wrung out the hotel towels he’d used to sop up water from the back seat of his car, his pants splattered with mud.

The flash flooding followed 6.44 inches of rain that fell in Greater Portland on Wednesday and early Thursday morning, washing out roads and flooding basements and first floors of businesses, homes and public buildings.

Wednesday’s rainfall was the highest 24-hour total in city history that wasn’t related to a designated tropical storm. Portland got 2.57 inches of rain from 9 to 10 p.m. alone, and another 1.64 inches in the following hour, said John Jensenius, a meteorologist with the National Weather Service in Gray.

There were no reports of injuries from the storm. It was part of a slow-moving system, powered by tropical moisture and clouds soaring far higher than in usual summer storms, that lashed communities from Maryland to New England.

On Thursday, officials in several counties were still assessing the cost of damage to roads and other infrastructure, said Lynette Miller, spokeswoman for the Maine Emergency Management Agency. Damages must reach about $1.8 million before the state can ask for federal disaster relief, she said, and no communities asked for state assistance during the storm. Gov. Paul LePage’s office did not respond to inquiries Thursday about a possible disaster declaration.

“We have a pretty high bar to hit,” Miller said.

In all, the city of Portland received 841 phone calls, several hundred more than usual, city spokeswoman Jessica Grondin said Wednesday.

Roads that had been closed overnight – including Marginal Way in Portland, a section of Route 1 in Scarborough, and others in Falmouth and South Portland – were opened to traffic Thursday morning.

In Portland, 13 manhole covers that had been washed out of place on flooded streets had been replaced.

Part of the sidewalk on High Street near Commercial Street collapsed about 3 a.m., and city officials said they were evaluating the intersection of the Back Cove and Eastern Promenade trails at Tukey’s Bridge. The section remained closed Thursday because of damage.

“Deering Oaks pond is still severely overflowed,” Grondin said. “They drained it a foot last night in anticipation of rain, but no one expected this much rain.”

Water also damaged the first floor of Portland City Hall, as well as Merrill Auditorium, where cleanup crews have been working since 10 p.m. Wednesday to dry out the venue before a concert scheduled for Sunday.

Only about 10 electricity customers of Emera Maine were still without power by 6 p.m. Thursday, down from about 3,300 who lost power at the storm’s peak, mostly in Lincoln County. About 116 Central Maine Power customers remained without electricity at 10 p.m., also mostly in Lincoln County.

The Maine Department of Environmental Protection had received three calls by Thursday afternoon from homeowners or businesses in Saco, Freeport and Lewiston reporting spills from heating oil tanks in flooded basements or outside.

“But we do expect that number to increase” as homeowners check for damage, said DEP spokeswoman Jessamine Logan. Anyone needing to report a spill should call (800) 482-0777 for guidance on how to proceed. In some instances, the DEP will send hazardous materials cleanup crews to homes.

The Coast Guard reported that several boats either had been swamped or set adrift during the storm. One 20-foot boat capsized in Portsmouth Harbor in New Hampshire, and others in Boothbay Harbor and Portland Harbor took on water, a Coast Guard spokesman said. There were no reports of major marine-related damage or injuries.

Rainwater overwhelmed the retention pond at Exit 15 off Interstate 295 in Yarmouth, flooding the ramp and closing the exit, according to the Maine Department of Transportation. The retention basin and ramp were part of the state’s $6 million redesign of the Exit 15 area.

“There’s just no drainage that can handle the amount of water that came in such a short period of time,” said MDOT spokesman Ted Talbot.

Once it stopped raining, the water cleared quickly and “we were able to open (the ramp) up very early (Thursday) morning,” he said.

The storm washed out road shoulders in several communities, including Richmond, Bowdoin and along Route 1 in Freeport and Brunswick, Talbot said,

In Freeport, sections of Upper Mast Landing Road collapsed, exposing drain pipes and opening up a deep ditch at the road’s edge.

Several roads were still partially closed Thursday morning in Freeport, where shoulders had washed out. On Cheehawk Road in South Freeport, water spilled over the dirt road after a culvert became blocked by branches and debris. The cascading water washed away almost half the road, but crews had it reopened by 9 a.m.

In the Northeast, the hardest-hit areas were Long Island’s Suffolk County, which declared a state of emergency after what County Executive Steve Bellone called an “unprecedented” deluge.

“It’s not just how much rain fell, it’s how fast it fell,” Accuweather senior meteorologist Jack Boston told The Associated Press. Boston called the storm a once-every-50-years event.

“We’re talking about billions and billions of gallons of water, and it all has to go somewhere,” he said.

The storm formed Tuesday south of Baltimore, according to Boston, and hit that city with its highest rainfall total in 81 years, The Associated Press reported. From there it swept across New Jersey – following a track similar to a typical winter storm – and dumped nearly 9 inches of rain in Millville. Rain fell at a rate of up to 2 inches per hour in Rhode Island, stalling cars and sweeping manhole covers away.

At the La Quinta in Portland, about a dozen hotel guests milled around the parking lot Thursday morning, some talking on cellphones to insurance agents. Several of the roughly 100 cars in the lot sat askew in their spaces, pushed around when the lot flooded. Guests made their way around puddles and piles of mud to check on their cars. Some car alarms blared, triggered by short circuits and water damage.

Jose Tobar Jr. and his wife, Debbie, assessed the damage to their minivan. The New York couple said their car started, but they were waiting for an insurance representative to meet them. The cup holders and trunk of the car were still full of water.

“A lot of water came pouring out of the tailpipe when we started it,” Jose Tobar said.

Spechler, another hotel guest, was staying on the fourth floor, but said first-floor guests told him water had been up to their ankles before they were moved to higher floors in the middle of the night.

A hotel clerk wearing rain boots said she had been told not to speak to the media, and managers of the hotel did not return calls for comment.

Rugs hung over the railings outside, and a mark on the side of the building showed that water had risen nearly to the bottom of the hotel’s first-floor windows.

Copeland, who is visiting from Wichita, Kansas, didn’t let the inconvenience of a flooded car get her down. She was hoping to get a new rental car and be on her way to Bar Harbor, where she plans to go whale watching.

“We’re just kind of enjoying the morning,” she said. “I’ve got coffee, so life is good.”

Staff Writers Edward D. Murphy and David Hench contributed to this report.