One of the largest convulsions of tornado activity in U.S. history left a swath of death and debris from Oklahoma to North Carolina and Virginia, killing at least 44 people, disrupting power service for thousands, and leaving many others injured or huddled in shelters.

The three-day outbreak included 241 tornadoes reported over 14 states, according to AccuWeather.com, noting that the spate of twisters is likely to rank among the most active ever recorded.

Meteorologists warned that another storm system was likely to plague the central and southern plains early this week and move east, possibly striking some of the same areas.

The storm system saved some of the worst destruction for last as it moved east.

In North Carolina, at least 22 people were reported dead as storms slammed through the state Saturday night. At least 11 were killed and 50 injured in Bertie County, a rural peanut- and chicken-farming region in the state's northeast corner.

County manager Zee Lamb said a twister apparently tore a course of destruction a half-mile wide and five to seven miles long as it moved northeast from the town of Askewville. Lamb said 75 homes appeared to be destroyed — although in some places, he added, "you can't tell where there was a house and where there wasn't a house."

"Where there were homes, there's nothing underneath it now," he said. "You've got trucks blown across the street. You just don't realize how powerful these storms are until you experience them."

Gov. Bev Perdue declared a state of emergency, suspending restrictions on work hours for truck drivers — to allow for the delivery of goods to affected areas — and for utility workers, since tens of thousands remained without power.

Lamb said the people of Bertie County had begun looking out for one another: As of Sunday evening, no one had checked into the shelter officials had opened.

"Neighbors are taking in neighbors; relatives are taking in relatives," Lamb said. "I'm not aware of anybody who doesn't have a place to stay tonight."

In Virginia, storms and flooding left at least five people dead and caused power outages around the state and a mudslide in the southwest.

Virginia Gov. Bob McDonnell declared a state of emergency. His office said he would travel Monday to the southeastern county of Gloucester, where three people died Saturday and others were injured when a tornado touched down over a 12-mile path.

The twister lifted part of the roof off a middle school and destroyed several homes, officials said.

In nearby Surry County, a Dominion Virginia Power plant was damaged when a tornado hit the switchyard and cut off the electrical feed from the grid to the station.

Both of the station's nuclear reactors shut down automatically, and backup diesel generators kicked in to provide electricity, according to the company.

"No release of radioactive material has occurred beyond those minor releases associated with normal station operations," the company said in a prepared statement.

Virginia officials said flash flooding killed two people in Waynesboro, in the Shenandoah Valley.

The destruction began in Tushka, Okla., on Thursday night, when storms totaled the local high school and killed two people.

On Sunday, amid warnings of more punishing weather in the days ahead, residents were calling the local sheriff to ask about places to ride out the next round.

"We've had enough," Atoka County Sheriff's Deputy Dennis Eldridge deadpanned in a phone interview Sunday afternoon. "That's all we need."

From Oklahoma, the storm system moved on to kill seven people in Arkansas, seven in Alabama and at least one in Mississippi.

AccuWeather officials said the extreme weather is the result of particularly warm water in the Gulf of Mexico, which supplies warm, moist air that significantly boosts storm power. Southwesterly wind in the upper atmosphere and southerly to southeasterly wind in the lower atmosphere created twisting motions and wind shear that made tornados more likely.

It's the deadliest tornado outbreak since 2008, when more than 50 people were killed on "Super Tuesday" as many states were voting in presidential primaries.