Officials from rain-soaked states in the Northeast said Wednesday the worst is yet to come, as rivers and streams continue to rise dangerously high, and weather experts call for yet more rain in the forecast.

"This is the worst flooding by far I’ve seen in my 12 years as governor," New York Gov. George Pataki told FOX News Wednesday afternoon. "The rivers haven't yet peaked ... we’re going to need massive federal help for the recovery."

Although the sun was finally shining in Washington, D.C., after days of torrential downpours, the dwindling storm moved through New York and New England Wednesday, forcing thousands of people from their homes, including more than 2,200 who fled from a rising Maryland lake. Rivers were still rising in much of the region. Numerous highways were blocked by flooding and washouts, including more than 200 in Virginia.

A section of interstate highway was washed away in New York state and least 12 deaths were blamed on the weather. Three people were missing. More than 70 people from seven Delaware River towns have been evacuated in Warren County, N.J.; the water in Phillipsburg is expected to reach nearly 17 feet above flood stage at 2 a.m. EDT.

Authorities ordered the mandatory evacuation of 150,000 to 200,000 people from Wilkes-Barre, Pa., and surrounding areas along the Susquehanna River, a Luzerne County official said. Virtually the entire state of Pennsylvania was under a flood watch or warning.

Wilkes-Barre was devastated by flooding in 1972 by the remnants of Hurricane Agnes, is now protected by levees. But county officials said the Susquehanna was expected to crest just a few feet from the tops of the 41-foot floodwalls.

Luzerne County Commissioner Todd Vonderheid said officials worried about the stability of the levees because the water was expected to press up against them for 48 hours.

"It is honestly precautionary," Vonderheid said. "We have great faith the levees are going to hold."

There are only 43,000 people in the town of Wilkes-Barre and approximately half of them — located in the southern half of the city — are under a mandatory evacuation order, FOX News has learned. Surrounding Wilkes-Barre, there is a flood plain that comprises several other townships, such as Hanover Township and Kingston. These areas may be evacuating, as well.

"20,000 people have lost power. … we’ve taken several people off rooftops," Pennsylvania Gov. Ed Rendell told FOX News. "We’re coping as best we can ... the worst part is yet to come."

A dozen helicopters from the Pennsylvania National Guard, the state police and the U.S. Coast Guard plucked stranded residents from rooftops in Bloomsburg, Sayre and New Milford, and about 700 of National Guard personnel were preparing to distribute ice, water, and meals ready to eat.

"We don't have anywhere to go," evacuee Mehader Mekonne said Wednesday at a shelter in Montgomery County, Md.

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The largest evacuation was ordered in an area surrounding Lake Needwood at Rockville, Md., which was approaching 25 feet above normal Wednesday, Montgomery County officials said.

Engineers found weakened spots on the lake's earthen dam, with water seeping through in places, said Bruce Romer, the county's chief administrative officer.

By Wednesday morning, police and rescue crews had evacuated an estimated 2,200 people from 500 apartments and 700 homes, Romer said. About 100 people refused to leave, he said. If the dam were to break, it could flood some areas as much as 20 feet deep, officials said.

Maryland Gov. Robert Ehrlich said Wednesday he couldn't give any guarantees as to when evacuated residents could return to their homes.

"We are obviously continuing to monitor the situation. Fortunately, the sun has come out around the state of Maryland," Ehrlich said.

He noted that the Eastern Shore has suffered crop damage totaling in the tens of millions of dollars. Many roads are unusable in that area, as well, many of them local.

The soaking weather was produced by a low pressure system that had stalled just out to sea since the weekend and pumped moist tropical air northward along the East Coast. Binghamton, N.Y., measured a record one-day total of 4.05 inches of rain on Tuesday. Although the bulk of the rain moved out of the area Wednesday, meteorologists said more showers and occasional thunderstorms were possible along the East Coast for the rest of the week.

New York state officials said two truckers were killed early Wednesday when they drove into a chasm that a flooded creek had carved across all four lanes of Interstate 88, about 35 miles northeast of Binghamton. The hole was 25 feet deep, state police said.

Thousands people were evacuated from communities across New York state, including hundreds in the Binghamton area. Whole villages north of Binghamton in rural Delaware County were isolated by high water.

"We have significant flooding throughout the county," said Delaware County planning director Nicole Franzese. "Widespread power outages, bridges washed out, roads washed out, the National Guard was operating all night."

Ten New York counties declared states of emergency.

I-81 also was closed at Lenox in northeastern Pennsylvania, where the small towns of New Milford and Lanesboro were evacuated, state police said.

Rendell declared a disaster emergency in 46 of the state's 67 counties Wednesday and the National Guard had been sent into Schuylkill County, west of Allentown, late Tuesday to help evacuate residents.

The Pennsylvania Turnpike was closed near Fort Washington, in the Philadelphia area, and some commuter trains in the area had to skip flooded stations.

Along the Delaware River, more than 1,000 people had left low-lying areas of Trenton, N.J. Upriver, a police helicopter had to be used to rescue five people who had not heeded an evacuation order on an island near Port Jervis, N.Y., said Lt. Gerald Lewis of the New York State Police.

"When we tell these people to evacuate, we really mean it," Lewis said.

New Jersey state workers in buildings along the Delaware prepared to leave work early and Trenton Mayor Doug Palmer called for water conservation after the debris-choked Delaware forced a shutdown of the city's water filtration system. The mayor said more than two days of drinkable water remained.

In addition to the two deaths in New York, the weather was blamed for two traffic deaths in Pennsylvania and one in Maryland. A 15-year-old boy and a would-be rescuer drowned in a Pennsylvania lake. Three people died in western Maryland when they were washed out of the bed of a pickup truck.

Elsewhere in Maryland, two youths, ages 14 and 15, were missing near a swollen creek at Keymar, said state police 1st Sgt. Russell Newell. Teams in Virginia searched for an 8-year-old girl swept away by high water in Alleghany County.

The Associated Press contributed to this report.