Residents leave buildings before the arrival of Hurricane Irene at downtown Manhattan in New York
Residents leave buildings before the arrival of Hurricane Irene at downtown Manhattan in New York August 27, 2011. Mayor Michael Bloomberg sternly warned New Yorkers to follow the city's unprecedented mandatory evacuation orders on Saturday, saying approaching Hurricane Irene is "life-threatening" and "not a joke." Some 370,000 of the city's more than 8 million residents are under orders to leave their homes in low-lying and waterfront areas, largely in the boroughs of Brooklyn and Queens and in the financial district in downtown Manhattan. Reuters

Hurricane Irene 2011 is on a path to become the East Coast storm of a lifetime, claiming lives, pouring destruction, and shutting down New York, America's largest city, before the storm even arrives. Irene has already claimed three lives in North Carolina and one in Virginia.

Irene is packing winds of 90 miles per hour and inflicting torrential rainfall and damage in North Carolina and Virginia.

Curfews are in effect in North Carolina, and the Pentagon has ordered troops on stand by ready to assist if necessary in hopes of avoiding another Hurricane Katrina-type disaster. Power failures have already reached 300,000 in Virginia, and more than 2.5 million Americans along the East Coast I-95 corridor are under evacuation orders, including 300,000 in New York.

New York has already effectively shut down Saturday before the storm arrives in an unprecedented closing of transit systems. Mandatory evacuation orders are in place for some sections of towns, and New York Mayor Michael Bloomberg warned Saturday the city could be effectively shut down for days without power or transit, if not indefinitely.

All metropolitan airports are closed, and JFK, near the water in Queens County, is a major international hub that is exposed to high risk of damage, as are low-lying areas of the city, including the Financial District which could take on feet of water mixed with salt water from the Atlantic as Irene surges inland.

Bloomberg stressed that residents urged to evacuate must heed the warnings since it could mean a matter of life or death. Since New York is in the direct path of Irene, the city could suffer a rare direct hit, with four to seven feet of storm surge in low-lying, exposed areas, and heavy rainfall and winds throughout.

The mayor said the city's subways likely won't reopen on Monday though the storm should have already departed and that power is in some Manhattan areas likely won't be back on for days longer. The extended partial shutdown poses a major blow to New York before Irene even strikes, since the subway system carries an average of about five million people per day.

At the moment, Bloomberg's primary concern was avoiding loss of life. He warned residents that electricity might have to be shut off before the storm knocks it out. He also said warnings must be taken seriously, since flood waters could rise from surge and rainfall in low-lying areas.

Heed the warnings. It isn't cute to sit there and say, 'I'm tougher than any storm. They don't know what they're talking about,' said Bloomberg, in a press conference Saturday. I hope this is not necessary, but it's certainly prudent to protect your life. And you putting our first responders' lives in danger, where if you need them to respond later on for something that you could have prevented, just isn't smart.

But before Irene reaches New York the storm is ravaging North Carolina's coastline and Virginia's coastline and moving up the east coast in a northerly direction after making landfall this morning as a Category 1 storm.

Four people, including an 11-year-old boy, have been killed in the storm thus far, and states of emergency and hurricane warnings extend up virtually the entire East Coast.

As the latest Hurricane Irene update shows the storm is likely to make a direct hit on New York late Saturday night or Sunday morning at Category 1 strength. Officials say citizens must not take Irene's Category 1 classification lightly, since the storm has a wide swath and pouring rains. Combining with storm surge, severe flooding could be a problem, particularly in low lying areas.

Also, Bloomberg said Saturday the city may have to shut off power downtown in order to protect lines from surging salt water. Residents who have not evacuated that live in the downtown area and other low-lying areas prone to hurricane storm surge can expect the city to shut down their power, Bloomberg said.

You can plan on the possibility of no power downtown, the mayor said.

He also noted power may not return for an indefinite period.

Bloomberg said Consolidated Edison Co. of New York will make the final decision about whether to cut the power in the next hours as the storm approaches and possibly strikes the city, likely with a rare direct hit. He said the decision will have to be made in advance of water rising, so storm track will likely be the determining factor.

New York's subway system has never been shut down because of weather and rarely have large-scale pre-emptive power outages been employed. But the city has only seen a few hurricanes make direct hits in the past 200 years. In September 1821, a hurricane flooded the southernmost tip of Manhattan in an area that now includes Wall Street and the World Trade Center memorial. And in 1938, a now-famous storm called the Long Island Express came hit neighboring Long Island, killing 700 up the East Coast.

The most dangerous thing we have to deal with is the storm surge and there is no indication that the forecast for that has changed. Mayor Bloomberg said. There is also serious risk of falling tree limbs in our parks.

Bloomberg said Consolidated Edison must ensure that facilities aren't damaged in the effort to spare long-term effects from Hurricane Irene. Since forecast models show Irene is likely to still be packing hurricane force winds of 75 miles per hour when it reaches the city, there's only so much the city can do.

The most important thing is to make sure (Consolidated Edison) facilities aren't damaged, which would take a long time to repair. If salt water gets into the underground cables and those cables are carrying electricity, there is a real chance of damage to those lines, he said. There is a lot less chance of damage to the lines if those power cables are not carrying power.

But Bloomberg's primary focus was getting New Yorkers to obey evacuation orders.

Let's stop thinking this is something that we can play with, Bloomberg said. Staying behind is dangerous. Staying behind is foolish and it's against the law.