The East Coast ramped up emergency preparations on Saturday for Hurricane Sandy, a monstrous and deadly storm that forecasters said could severely impact cities and towns with heavy flooding and fierce winds.
Sandy moved slowly off the coast of South Carolina as a Category 1 hurricane, having left at least 45 dead in its wake in the Caribbean and Central America.
The storm tracked northeasterly in the Atlantic, but was expected to boomerang toward the shore with its enormous breadth and begin to seriously impact heavily populated areas as early as Sunday. Rainfall totals in some areas could reach historic proportions.
The target area was hard to predict. Some landfall computer models showed the storm striking somewhere between the border of North Carolina and Virginia north to Connecticut. That area includes some of the most densely populated areas of the country.
Residents along the 700-mile stretch sandbagged low-lying areas, secured and fortified homes and buildings, and packed stores to stock up on bottled water, food, and batteries in anticipation of widespread power outages.
Presidential campaigns adjusted their schedules to account for Sandy's potential impact. At least one state that could be hit hard, Virginia, is a hotly contested battleground in the November 6 election.
Several states declared emergencies and accelerated storm preparations. New Jersey was the first to announce mandatory evacuations and New York prepared to possibly suspend subway and other transportation services.
"We have to prepare for the worst here," New Jersey Gov. Chris Christie said as authorities ordered the state's barrier islands from Sandy Hook south to Cape May cleared out by Sunday afternoon. Those at Atlantic City casinos also must leave by then.
Sandy is responsible for at least 29 deaths in Haiti, Civil Protection spokesman Joseph Edgard Celestin said. Four Haitians remained missing. Another 16 people were reported killed in Cuba, Jamaica, Panama, the Dominican Republic and Puerto Rico.
Is Sandy another "Perfect Storm?"
The biggest threat to the United States involves the hurricane colliding with a cold front from the West, creating a "superstorm" that could stall over the Eastern seaboard for days.
Such a confluence would "energize this system so we'll actually get an intensification of this system," said Louis Uccellini, who is responsible for environmental prediction at the National Oceanic and Atmospheric Administration.
James Franklin of the National Hurricane Center said Sandy is expected to move slowly.
"The large size of the system and its slow motion will mean a long-lasting event with two to three days of impacts," Franklin said.
Sandy's scenario is not unlike the weather system that led to 1991's "Perfect Storm," when moisture flung north by Hurricane Grace combined with a high pressure system and a cold front to produce a tempest in the north Atlantic over Halloween. But Grace never made landfall.
At 2 p.m. ET on Saturday, the National Hurricane Center said Sandy was about 335 miles southeast of Charleston, South Carolina. It was a Category 1 hurricane with winds of 75 mph.
She produced tropical-storm-force winds over the Atlantic from the northern Bahamas to near the North Carolina coast, the center said. The storm was moving to the northeast but was forecast to cut back toward the coast.
Sandy has taken on a lopsided form and its heaviest winds should be in the northern and eastern sections of the storm as it nears land -- and be directed inbound toward the coastline. Forecasters predicted a large ocean storm surge.
The surge is likely to hit during a full moon, when tides are the highest, worsening the potential for coastal flood damage.
"Forget about the category with this," said CNN meteorologist Rob Marciano. "When you have trees with leaves on them still, this kind of wind and rain on top of that, you're talking about trees that are going to come down, power lines are going to be out and the coastal flooding situation is going to be huge."
Areas of the Appalachian mountains prepared for heavy snow.
Sandy responsible for at least 45 deaths
Computer models predicted Delaware, Maryland and Virginia could see up to a foot of rain, according to the CNN Weather Unit. Isolated spots could see the worst rains in 500 years.
The District of Columbia, Pennsylvania, Maryland, Virginia, New Jersey, Connecticut, North Carolina and New York have declared states of emergency, while Maine's governor signed a limited emergency declaration. Delaware's governor has said the state will issue a mandatory evacuation of its coastline, if the storm stays on path.
With early voting for the presidential election already
Republican nominee Mitt Romney canceled scheduled campaign events in Virginia on Sunday. President Barack Obama is slated to travel to Florida.
Vice President Joe Biden canceled his visit to Virginia Beach on Saturday.
Early voting kicked off Monday in Washington and is scheduled to start Saturday in Maryland. On Friday, Maryland Gov. Martin O'Malley left open the possibility that the vote could be rescheduled, or polling stations moved inland.
New York weighed suspending subway, bus and commuter rail service with a decision on whether to take that step expected Sunday, Gov. Andrew Cuomo said.
"New Yorkers need to take action now to protect themselves, and as the transportation system prepares to possibly suspend service, no one should wait until the last minute to prepare," he said.
Connecticut Gov. Dannel Malloy said his state would have 400 National Guard troops prepared to assist with recovery efforts, as needed.
"Please take this as seriously as we're taking it," he said, noting that forecasters are predicting 36 hours of sustained winds in the area.
All Northeast airports will experience delayed and canceled flights.
American, United and Spirit airlines announced late Friday they would waive fees for passengers traveling in and out of many Atlantic coast cities who want to change plans.
Amtrak will deploy preparedness crews and equipment along tracks along its busy Northeast line to remove debris, make repairs and mend downed electrical lines, if necessary.
Washington's power company has ordered 2,500 additional linemen, 400 tree cutters and has beefed up call center staff, according to affiliate WJLA. "We'll open up additional staging areas," PEPCO executive David Velazquez said.
In Maryland, the Baltimore Gas and Electric Company expects that several hundred thousand customers could be affected, as early as Sunday.
CNN Weather estimates that damage from Sandy could reach $3.2 billion. This estimate is based only on wind damage and does not include flooding.
Sandy will be studied for years to come, Uccellini said.