"Residents should not travel unless necessary," Codey's office said in a statement. "The public can expect significant delays."
Connecticut Gov. Jodi Rell issued a similar warning to motorists in her state, where as much as 8 inches (20 cm) of rain fell, flooding at least one heavily traveled rail line, her office said.
Meanwhile, airlines scrambled to catch up on a backlog of canceled and delayed flights. Airlines canceled some 600 flights at the New York area's three major airports on Sunday as wind gusted to 48 mph, according to the Port Authority of New York and New Jersey. Dozens more flights were canceled in Philadelphia, Boston and elsewhere in New England.
Delays at New York's La Guardia Airport and Boston's Logan International Airport are averaging about two hours, while flights to Newark International Airport are running three hours behind. Flights to Washington Dulles International Airport and Philadelphia International Airport are delayed up to an hour and a half. Meanwhile, flooding forced several small airports in New Jersey, including Caldwell and Teterboro, to close, with no information as to when they would reopen.
Flooding caused cancellations and delays for Amtrak passengers between Washington and Boston.
Across the region, new rainfall records were set with New York City's Central Park measuring 7.57 inches (19.23 cm), marking the wettest day in 125 years, officials said.
Winds gusted as high as 75 miles per hour (120 km per hour) in southern New England, according to the National Weather Service, whose meteorologists forecast wind speeds will pick up again over New England in a day or two as the storm's center moves north.
"I have never seen anything like this," said Ted Nichols, in Wilton, New Hampshire, after his basement was flooded and he had trouble getting to work on Monday because many roads were closed around his home.
BLANKETED WITH SNOW
Parts of northern New York state, Pennsylvania, Vermont, New Hampshire and western Massachusetts were blanketed with snow at a time many trees and flowers were already blooming. As much as 17 inches of snow fell in Vermont, with flakes still falling Monday across sections of Pennsylvania, upstate New York and Maine.
The National Weather service forecast more than 12 inches (30 cm) of snow along northern New England and New York's Adirondack Mountains, according to its Web site.
In Boston, the city's 111th annual Marathon went off on schedule with about 20,000 runners runners donning plastic garbage bags to hold off the rain and stay warm.
"I've not run in conditions this bad," said Mike Stirling, one of the 23,500 runners entered in the race. "Colder but drier, wetter but warmer, I've done."
In Maine, however, Portland called off its Patriot's Day 5-Miler race for the first time in 78 years, because police were too busy with flooding, downed trees and power outage to secure the race route.
People were evacuated from flooded homes and businesses throughout the region Monday, with suburbs north of New York City among the hardest hit. In Mamaroneck, resident Nicholas Staropoli said a truck near his home "actually floated up on the riverbank."
Mamaroneck police and firefighters spent the night rescuing residents from about 60 to 70 homes, said Town Administrator Stephen Altieri. More than two dozen National Guard members used trucks and Humvees to help evacuate low-lying sections of the town. The state had activated 3,200 Guard members.
"There was debris flowing down the river like you wouldn't believe--refrigerators, I mean, you name it, it was going down the river," homeowner John Vitro said of the Mamaroneck River.
The combination of heavy rain and unusually high tide rolling up the Hudson River pushed the Croton River out of its banks in Croton-on-Hudson, in northern Westchester County. Cars were stalled in water on numerous roads and several major highways were closed at times by flooding. All public schools in Westchester County were closed Monday.
New Jersey also had school closings, highways blocked by water and dozens of residents being evacuated from homes, authorities said. Hundreds of people had been evacuated from their homes in southern West Virginia as crews worked to pump water from a private lake near Hamlin to keep an unstable earthen dam from collapsing.
If the dam breaks, millions of gallons of water could pour into Hamlin, Mayor Brian Barrett said Monday. "We're being told it could be eight or nine feet of water," Barrett told the Herald-Dispatch of Huntington.
Coastal residents were urged to evacuate in parts of Maine, and a nursing home in Portland was evacuated as a precaution, state officials said. In southeastern New Hampshire, parts of downtown Newmarket were evacuated because of flooding.
Nearly a half-million homes and businesses had lost power from North Carolina to Maine.
"We have incredible amounts of damage," said Steve Costello, a spokesman for Central Vermont Public Service, describing power lines brought down by the heavy snow. "I've never seen anything like it."
Fierce wind toppled trees onto a northern New Hampshire highway as Bob Eastman was driving through on Monday morning. "It was a wonder it didn't blow you off the road," he said.
Eastman said highways crew used chain saws and snowplows to remove the fallen trees.
In Union City, N.J., a large section of a 4-foot-thick, 50-foot-high stone wall collapsed onto a busy road during the night, and rescue workers used heavy machinery and dogs Monday to see if any cars had been buried. "There could be, and that's the assumption we have to operate under," said David Curtis, deputy chief of North Hudson Regional Fire and Rescue.
An apartment building atop the wall was evacuated.
One person was killed by a tornado in South Carolina, and two died in car accidents--one in upstate New York and one in Connecticut. The storm rattled the Gulf states Friday and Saturday with violent thunderstorms after taking Texas with at least two tornadoes, and it was blamed for five deaths in Texas and Kansas.