WASHINGTON // Hurricane Sandy - upgraded again yesterday just hours after forecasters said it had weakened to a tropical storm - headed north from the Caribbean and was expected to pummel the eastern United States.
The US National Weather Service said the storm was expected to make landfall early Tuesday near the Delaware coast, then hit two winter weather systems as it moves inland, creating a hybrid monster storm that could bring torrential rain, high winds, and up to 60 centimetres of snow.
Even if Sandy loses strength and makes landfall as something less than a hurricane, the combined storm was expected to bring misery to a huge section of the eastern US. A 1,300-kilometre wide swath of the country could see 80 kph winds regardless of Sandy's strength.
Experts said the storm could be wider and stronger than Irene, which caused more than US$15 billion (Dh55bn) in damage when it struck in August 2011, and could rival the worst East Coast storm on record.
Forecasters said hurricane-force winds of 120 kph could be felt 160km away from Sandy's centre.
Sandy killed more than 40 people in the Caribbean, wrecked homes and knocked down trees and power lines.
Up and down the coast, people were cautioned to be prepared for days without electricity. Beach towns in New Jersey began issuing voluntary evacuations and protecting boardwalks. Atlantic City casinos made contingency plans to close, and officials advised residents of flood-prone areas to stay with family or be ready to leave. Several governors declared states of emergency. Airlines said to expect cancellations and waived change fees for passengers who want to reschedule.
"Be forewarned," Connecticut Governor Dannel P Malloy. "Assume that you will be in the midst of flooding conditions, the likes of which you may not have seen at any of the major storms that have occurred over the last 30 years."
"It's looking like a very serious storm that could be historic," said Jeff Masters, meteorology director of the forecasting service Weather Underground.
With a rare mix of three big merging weather systems over a densely populated region, experts predict at least $1 billion in damage.
Sandy, having blown through Haiti and Cuba and leaving 43 dead across the Caribbean, continued to barrel north. A wintry storm was moving across the US from the west, and frigid air was streaming south from Canada.
If they meet Tuesday morning around New York or New Jersey, as forecasters predict, they could create a big, wet mess that settles over the nation's most heavily populated corridor and reaches as far west as Ohio.
Government forecasters said there is a 90 per cent chance - up from 60 per cent two days earlier - that the East Coast will get pounded.
"It's going to be a long-lasting event, two to three days of impact for a lot of people," said James Franklin, forecast chief for the National Hurricane Centre.
With much of the US East Coast in the storm's path, residents of the nation's most densely populated corridor contemplated whether to heed the dire warnings.
"You know how many times they tell you, `This is it, it's really coming and it's really the big one,' and then it turns out not to be?" said Alice Stockton-Rossini as she packed up to leave her home a few hundred metres from the ocean in Ship Bottom, New Jersey.
"I'm afraid people will tune it out because of all the false alarms before, and the one time you need to take it seriously, you won't. This one might be the one."