Hurricane Sandy, the monster storm bearing down on the East Coast of the United States, strengthened on Monday after hundreds of thousands moved to higher ground, public transport shut down and the stock market suffered its first weather-related closure in 27 years.
About 50 million people from the Mid-Atlantic to Canada were in the path of the nearly 1,000-mile-wide (1,600-km-wide) storm, which forecasters said could be the largest to hit the mainland in US history. It was expected to topple trees, damage buildings, cause power outages and trigger heavy flooding.

The US National Hurricane Center (NHC) said on Monday the Category 1 storm had strengthened as it turned toward the coast and was moving at 20 miles per hour (32 km per hour).

It was expected to bring a “life-threatening storm surge,” coastal hurricane winds and heavy snow in the Appalachian Mountains, the NHC said.

Nine US states have declared states of emergency, and with the US election eight days away President Barack Obama canceled a campaign event in Florida on Monday in order to return to Washington and monitor the US government’s response to the storm.

“This is a serious and big storm,” Obama said on Sunday after a briefing at the federal government’s storm response center in Washington.

“We don’t yet know where it’s going to hit, where we’re going to see the biggest impacts.

Sandy killed 66 people in the Caribbean last week before pounding US coastal areas with rain and triggering snow falls at higher elevations as it moved north.

Forecasting services indicated early Monday the center of the storm would strike the New Jersey shore near Atlantic City on Monday night.

While Sandy does not pack the punch of Hurricane Katrina, which devastated New Orleans in 2005, it could become more potent as it approaches the US coast.

Winds were at a maximum of 85 mph, the NHC said in its 8am (1200 GMT) report, up from 75 mph six hours earlier.

It said tropical storm-force winds reached as far as 485 miles from the center.

Seventeen people from the replica HMS Bounty abandoned ship while stranded at sea off North Carolina in the path of the hurricane, roughly 160 miles from the center of storm, the US Coast Guard said on Monday.

“The 17-person crew donned cold water survival suits and lifejackets before launching in two 25-man lifeboats with canopies,” the Coast Guard said, adding it was determining which aircraft or vessel was best-placed to launch a rescue.

The three-masted tall ship was built for the 1962 movie Mutiny on the Bounty.

New York and other cities and towns closed their transit systems and ordered mass evacuations from low-lying areas ahead of a storm surge that could reach as high as 11 feet.