Friday, August 26, 2011

Hurricane Irene A Dangerous Storm For The Eastern Seaboard

The expected arrival of the nearly 600-mile-wide Hurricane Irene this weekend means that states of emergency have been declared along the length of the eastern seaboard. Dangerous Irene is an usually wet and large hurricane in its overall size with tropical storm force winds extending out nearly 300 miles from the center. Climate scientists studying hurricanes have documented a 35-year warming trend of 1 degree Fahrenheit in ocean surface temperature. That 1 degree rise in surface temperature increases atmospheric water vapor available to feed hurricanes, increasing the area of tropical storm force winds and total rainfall amounts.

Depending on numerous factors, it could take New York City “weeks or months” to return to normal if the densely-populated city suffers a direct hit from Hurricane Irene. Apart from the potential loss of life in the most densely populated part of the America, history suggests that the economic damage could run into the tens of billions of dollars, depending on the severity of the storm and how close it comes to the City of New York. Unlikely but theoretically plausible scenarios could have the damage entering the realm of the costliest natural disasters of all time, and perhaps being large enough to have a materially negative effect on the nation’s gross domestic product.

The storm is poised to hit New York at a time when high tides reach their highest levels, which could amplify flooding in the city built around bays and rivers. Some experts predict a storm surge of five feet or more. Lower Manhattan could see streets under a few feet of water.

"In many ways, a Category 2 or stronger storm hitting New York is a lot of people's nightmare, for a number of reasons," said Susan Cutter, director of the Hazards and Vulnerability Research Institute at the University of South Carolina.

Even if the winds aren't strong enough to damage buildings made largely of brick, concrete and steel, a lot of New York's subway system and power lines are underground. The city's airports are close to the water, too, and could be inundated, as could densely packed neighborhoods. Hospitals were told to make sure generators were ready.

Areas of the city are only a few feet above sea level, making it particularly vulnerable to flooding. Sea levels were stable for about 2,000 years, but have been rising worldwide for the last century, most likely due to melting polar ice caps and glaciers, according to international and U.S. scientific estimates.

Global warming fills oceans with melting ice and swells the water itself, as it warms. Along the U.S. East Coast, where Hurricane Irene is headed, sea levels rose about six inches more than the global average in the last century, a total of about a foot overall. In New Jersey, for instance, sea level is rising about an inch every six years.

For every one-foot rise in sea level, U.S. scientists estimate a 36-58% increase in damage from storm surge. For a three-foot rise, the damage doubles or tripling of damages.

A few inches or a foot might not seem like much, but when that foot means the difference between the surf and your home, or your water treatment plant, it makes all the difference. The latest forecast from the National Hurricane Center for Hurricane Irene includes this warning:

STORM SURGE...AN EXTREMELY DANGEROUS STORM SURGE WILL RAISE WATER LEVELS BY AS MUCH AS 6 TO 11 FEET ABOVE GROUND LEVEL IN THE HURRICANE WARNING AREA IN NORTH CAROLINA...INCLUDING THE ALBEMARLE AND PAMLICO SOUNDS. STORM SURGE WILL RAISE WATER LEVELS BY AS MUCH AS 4 TO 8 FEET ABOVE GROUND LEVEL OVER SOUTHERN POTIONS OF THE CHESAPEAKE BAY...INCLUDING TRIBUTARIES...AND THE EASTERN SHORE OF THE DELMARVA PENINSULA. STORM SURGE WILL RAISE WATER LEVELS BY AS MUCH AS 3 TO 6 FEET ABOVE GROUND LEVEL ALONG THE JERSEY SHORE. NEAR THE COAST...THE SURGE WILL BE ACCOMPANIED BY LARGE... DESTRUCTIVE...AND LIFE-THREATENING WAVES.
Irene is expected to make landfall very close to Cape Lookout, North Carolina as a Category 3 hurricane early Saturday afternoon and then track across Pamlico and Albemarle sounds in eastern North Carolina during the late afternoon hours of Saturday. Irene is then expected to track very near the Mid-Atlantic coast as a Category 2 hurricane on Saturday night before making landfall on the southern New England coast just west of New London, Connecticut as a 95 to 100 mph hurricane right around early afternoon on Sunday. From there, Irene will track northeastward across central Massachusetts, southeastern New Hampshire and southwest Maine as a weakening Category 1 hurricane from late Sunday afternoon into Sunday evening. By late Sunday night and into Monday morning, Irene is forecast to track across central and northern Maine as a tropical storm before exiting into the Canadian Maritimes late Monday morning.

Related: The 9 Billion-Dollar Weather Disasters of 2011

Two video reports examine the possible effects of a direct strike by Hurricane Irene on New York City. Mayor Michael Bloomberg has discussed the possibility of shutting down the subway system and making other preparations ahead of the storm.


Video, courtesy of CBS News


Video, courtesy of ABC News GMA

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