Hurricane Irene update: Significant threats, even with Category 1

As hurricane Irene moves up the east coast, experts warn that even a storm downgraded to Category 1 can have major threats including tornadoes, coastal storm surges, and flooding.

By early afternoon Saturday, the center of hurricane Irene had moved north to about 50 miles west of Cape Hatteras, N.C., according to AccuWeather.com.

It was traveling inexorably NNE at about 15 miles per hour with 85-mph winds gusting to 115 mph. In New York City, some 400 miles away, rain and wind foretold Irene’s approach as the public transit system shut down and the region’s five major airports stopped taking incoming flights.

In anticipation of what are likely to be expensive response and recovery operations, President Obama has signed emergency declarations for nine states: North Carolina, New York, Virginia, Maryland, New Jersey, Connecticut, New Hampshire, Rhode Island, and Massachusetts.

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Meanwhile, tornado watches are in effect for parts of Delaware, New Jersey, Maryland, and Virginia.

That’s one of the dangers in assuming that a hurricane downgraded to Category 1 is somehow less dangerous. Such classification has no relationship to the likelihood or severity of tornadoes, coastal storm surges, or flooding. And it’s why state governors and other officials continue to urge maximum caution in the face of the approaching storm.

In New Jersey, for example, 98 percent of Cape May County has been evacuated.

“Over one million people have left the Jersey Shore over the past 24 hours, and there’s been very little disruption,” New Jersey Gov. Chris Christie reported at a press briefing Saturday afternoon.

The remaining concern, he said, was for about 600 senior citizens who so far have refused to leave their high-rise homes in Atlantic City. Gov. Christie has dispatched buses, state police, and state transit officials to urge those people to go to shelters.

“It’s true that I can’t force you to leave your homes, and I certainly wouldn’t arrest you for not leaving,” Gov. Christie said. “But I urge you to leave now.

In neighboring New York, Mayor Michael Bloomberg talked of the same kinds of dangers a Category 1 hurricane can include.

"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 at a press briefing Saturday. "There is also serious risk of falling tree limbs in our parks."

Some 370,000 New Yorkers 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.

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