Battered by a rainstorm that shut down roads, forced evacuations and prompted President Obama to declare a state of emergency, Rhode Island may be in for more misery Wednesday.

"We have some historic flooding going on in places we've never had flooding before," said Cranston, Rhode Island, police Lt. Stephen Antonucci. "We have numerous streets that are closed, and they're telling us the worst is still yet to come."

All eyes were on the Pawtuxet River, which runs through Cranston. The river stood at 20.64 feet as of about 7 a.m. ET -- nearly 12 feet above flood stage of 9 feet. It is forecast to crest at 20.7 feet Wednesday morning, according to the National Oceanic and Atmospheric Administration.

The state shut down parts of Interstate 95 in both directions. Obama extended a state of emergency on Monday for the entire state, freeing up federal dollars to help with relief efforts.

The culprit is a rainstorm that refused to leave after it formed Sunday night. It washed over the water-weary Northeast on Tuesday, flooding much of the already saturated region but focusing its withering power on Rhode Island.

In Yantic, Connecticut, the Yantic River set a record when it crested Tuesday at 13.6 feet -- 4.6 feet above flood stage.

Yet another record was predicted for Saxonville, Massachusetts, where the Sudbury River was expected to reach 13.4 feet Wednesday afternoon. Flood stage is 10 feet.

"I've been working here for over 10 years, and I really haven't seen anything like this in my career," said Tom Econopouly, a senior hydrologist at the Northeast River Forecast Center in nearby Taunton, Massachusetts.

In all, the storm system has dumped 8.75 inches of rain in East Providence, Rhode Island, 7.6 inches in downtown Providence and 5 inches in Cranston, he said.

Compounding the misery was that parts of the region were still trying to shake off the effects of a storm two weeks ago. With heavy winds and rain, this week's system has left thousands of customers without power.

A map on the National Weather Service's Web site shows coastline shaded in bright green from Maine to Delaware, indicating widespread flood warnings.

"We haven't seen the worst of it yet," Rhode Island Gov. Donald Carcieri said Tuesday night after 7 to 8 inches of rain had inundated much of his state.

Carcieri pleaded with Rhode Islanders to stay off the roads. "We are very concerned about flooding on the highways," he said.

The Blackstone River in Woonsocket and Pawcatuck River in Charleston were not expected to crest until 8 a.m. Wednesday, he said.

"None of us alive have seen the kind of flooding we are experiencing now," Carcieri said, calling the downpour an event that occurs once every 100 years to 500 years.

Sewage treatment plants around the state were swamped, with one in Warwick "completely inundated," he said. That led the Department of Health to order the closure of all beaches in the state. Emergency officials asked residents of affected areas to try to conserve water.

Carcieri urged residents of low-lying areas not to jeopardize their safety by refusing to comply with officials' requests to evacuate. He noted that some National Guard have been deployed to help.

Cranston Mayor Allan Fung said about 120 homes had been evacuated in the western part of the city.

A spokesman for National Grid Energy Services said 12,000 to 14,000 customers were without electricity in the Cranston area, where a substation was underwater. In Westerly, another 9,600 customers were in the dark, the spokesman said.

Gas was turned off in some areas, too, he said.

Shelters have been set up throughout the state, said Rhode Island Lt. Gov. Elizabeth Roberts.

"We are looking at historic levels," said Luke Peterson, assistant town manager for West Warwick.

The Pawtuxet River in Cranston and West Warwick, about 13 miles southwest of Providence, flooded a few weeks ago at record levels.

This time, Peterson said, reports predict the river, which reaches flood stage at 9 feet, will crest at 17.5 feet at Cranston. The river crested at nearly 15 feet more than two weeks ago.

"There's not a whole lot we can do," Peterson said. "If we try to hold back on our side, we'd make it worse for the neighboring community."

No deaths have been reported in Rhode Island.

That was also the case in Massachusetts, where 4 to 7 inches of rain had fallen in the eastern part of the state, said Scott MacLeod, a public information officer with the Massachusetts Emergency Management Agency in Framingham.

Most of the flooding occurred in southeastern Bristol County, where about 200 people were evacuated, he said.

Massachusetts Gov. Deval Patrick declared a state of emergency earlier this week and activated the National Guard, MacLeod said.

A handful of shelters were open, though few people were staying in them; there were no reports of power outages, MacLeod said.

"It's mainly flooding issues -- closed roads, flooded roadways and basements," he said.