The last hurricane to pass directly over the new York, in 1821, caused tides to rise 13 feet in one hour, flooding all of Lower Manhattan up to Canal Street. According to official estimates, a storm similar to the great Long Island Express of 1938 would cause $40 billion in damage if it hit Long Island now.

According to meteorologists, areas like the Hamptons, the eastern Long Island haven for New York's affluent, are at the highest risk.

New York is getting ready for Hurricane Irene, which is expected to strike the densely populated U.S. Northeast Saturday and Sunday. 

Flooding will be a major problem even if Irene spares the New York region as the tides are expected to be high in any case over the weekend due to a new moon, say experts.

Mayor Michael Bloomberg will hold a news conference Thursday at 9 a.m. in Queens to talk about the city's preparations for Hurricane Irene.

Hurricane Evacuation Zone Finder

If the storm followed the exact track of it, there could be considerable wind damage and tidal flooding out in those areas, James Aman, senior meteorologist with WeatherBug, told Reuters. There potentially could be some storm surge problems out around the eastern tip of Long Island, Rhode Island, Cape Cod, some of the areas around Boston that face Massachusetts Bay.

If Irene hits Long Island or southeast Massachusetts, the storm has the potential to be a $10 billion disaster, Weather Underground said in a blog post Wednesday.

Even the poshest homes in the region often lack hurricane-strength glass and wind shutters, which are standard in Florida, according to Michael Taylor, executive vice president for claims in the consumer unit at Chartis, the property insurance arm of AIG. These are things that will make homes a little more susceptible here if we do have high winds, he said.

New York City officials have begun preparations to evacuate residents from low-lying areas, if necessary.

The sense is that we're going to be facing a strong tropical storm with winds of 40 to 60 mph, said Emergency Management Commissioner Joseph F. Bruno.

Bruno added that the city's agencies were preparing for a worst-case scenario of a Category 1 hurricane with winds surpassing 72 mph and waters surging dangerously in low-lying areas, the Associated Press reported. Officials were getting ready to possibly evacuate the most frail and needy from hospitals and nursing homes.

Zone A, the part of the city most likely to be flooded, includes the southern tip of Manhattan as well as Brooklyn's Coney Island and the Rockaway Peninsula in Queens.

Evacuees will be able to avail public transport facilities before transit authorities cease operations, and they could use shelter on higher ground at dozens of city evacuation centers, Deputy Mayor for Operations Cas Holloway said.

In the event that any kind of evacuation was needed we would be using every available communication means and working with people in the local community, he said.

The officials are planning to shut down subway stations and tunnels ahead of time to reduce damage to the infrastructure, as these places are most likely to be flooded.

Officials asked residents to stock emergency supply kits at home, including bottled water, non-perishable food and a battery-powered radio.

Long Island emergency officials asked residents to be prepared in the event of being stranded this weekend. Nassau County Executive Edward Mangano said school buses might be used to evacuate residents to storm shelters. This is a good time to get prepared again in your homes. There's items that you should stock up on, those that need to move or possibly be evacuated. Perhaps seniors should think about having their medications refilled and having enough on hand, Mangano told CBS New York.

You have to recognize that you're living here on an island, and island living represents certain risks, Mangano said. And those risks appear now, at least, to be tracking toward us.

Officials haven't decided whether to close beaches or limit access to the water to reduce risk. Emergency management officials will be available all weekend to avert risks of the dangerous storm.