Damage from post-tropical Cyclone Sandy expected to be $20 billion NEW YORK, Oct. 30 (UPI) -- Post-tropical Cyclone Sandy pummeled the U.S. East Coast, leaving at least 11 people dead, streets flooded and some 6 million customers without electricity. The accelerating storm, which had 80 mph sustained winds when it made landfall near Atlantic City, N.J., around 8 p.m. EDT Monday, pressed on with maximum sustained winds of 75 mph early Tuesday and moved northwest at 18 mph, the National Hurricane Center in Miami said. The storm, which all but destroyed Atlantic City's famed Boardwalk as near-record-high Atlantic waves forced their way inland, was widely expected to be one of the most damaging ever to wallop the Northeast, from North Carolina to New England. Flooding near Atlantic City spread up to 18 miles inland. Connecticut Gov. Dannel Malloy said thousands of people were stranded by rising water along the coastline. He urged those in one-story homes to move to their roofs. "This is a Katrina-like warning we are issuing," he said. Hurricane-force winds extended up to 175 miles from the storm's center. Tropical-storm-force winds spread out 485 miles from the center, as far north as Canada and west to the Great Lakes. Forecasters warned of 20-foot waves hitting Chicago's lakefront and up to 3 feet of snow in parts of West Virginia and other states. In New York, a construction crane atop one of the tallest buildings in the city came loose in the storm and dangled 80 stories over a major thoroughfare across the street from Carnegie Hall. Government offices, businesses and schools throughout the region were closed. Roads, bridges and tunnels were closed. More than 13,000 airline flights were canceled. Subways were shut down from Boston to Washington, as were Amtrak and commuter rail lines. New York City taxis were ordered off city roads Monday night, Mayor Michael Bloomberg said. New York University Medical Center's backup power had failed, and the city was working to move patients to other facilities, he said. Hoboken, N.J., Mayor Dawn Zimmer told MSNBC half of the city was underwater, including the hospital and three fire stations. President Barack Obama, who returned to the White House Monday and met with top advisers, said, "Transportation is going to be tied up for a long time." He said it would likely take utility crews some time before they would even be able to begin making repairs. Obama late Monday night signed emergency declarations for Virginia and West Virginia, ordering federal aid to supplement state and local efforts. Damage from the storm could be as much as $20 billion, catastrophe-risk modeling firm EQECAT said. By contrast, Hurricane Irene, which slammed the region 14 months ago, caused $10 billion in damage. Insured losses from Hurricane Katrina in 2005 topped $45 billion, after adjusting for inflation. The 11 deaths were in Connecticut, Maryland, Pennsylvania, New Jersey and New York. A woman walking in Toronto was killed by a falling sign knocked down by high winds, police said.