Traffic jams and increased gas prices have already started as east coast residents flee Hurricane Irene.
The storm is supposed to hit North Carolina tomorrow and swirl up the coast beyond Boston this weekend.
Although Irene has been downgraded to a Category 2 storm, that still could mean 100 mph winds.
Obama says this could be a “historic hurricane.”
Bill Read of the National Hurricane centre says, “I would prepare for the worst and hope for the best.”
What exactly is the worst?
People from North Carolina to Maine are in danger of Irene's wrath.
In North Carolina, 3.5 million people have been urged to evacuate. In New York City's Zone A evacuation areas alone, there are 250,000 residents at risk.
Millions of people could lose power between North Carolina and NEw England, says meteorologist Chris Hyde.
Grocery stores are stocking themselves with water, flashlights and complete hurricane kits.
The MTA in New York has already announced that it will shut down at noon tomorrow. Atlantic City won't even be open to gamblers during the storm.
Coastal areas from North Carolina to New England could get 10-15 inches of rain over the next few days.
'Even if the winds aren't strong enough to damage buildings in a metropolis made largely of brick, concrete and steel, a lot of New York's subway system and other infrastructure is underground and subject to flooding in the event of an unusually strong storm surge or heavy rains,' says Newsday.
At Irene's worst, Philadelphia could be flooded with a couple feet of rain, says MarketWatch.
'In September of 1821, a hurricane raised tides by 13 feet in an hour and flooded all of Manhattan south of Canal Street, the southernmost tip of the city. The area now includes Wall Street and the World Trade centre memorial,' says Newsday.
'The New York metropolitan area will experience the worst conditions later Saturday night and Sunday with hurricane conditions possible along with destructive wind, heavy flooding rain, and storm surge with coastal flooding,' says Weather.com
According to the National Hurricane centre, 'poorly constructed homes are at risk for losing their roofs, high-rise windows can be broken and many shallow-rooted trees will be snapped off or pulled from the ground.'
'Irene may cause $13.9 billion in insured losses and $20 billion in overall economic losses due to lost hours at work, power outages, interruption of shipping and airline traffic, according to estimates by Kinetic Analysis Corp,' says Bloomberg.
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