The chatter about this weekend’s snowstorm has reached a fever pitch. And while snow total maps are de rigueur for any weather site worth its road salt, it’s the coastal flood impacts that could also go down in the record books and drive major damage.
Areas north and west of Washington, D.C. are under a blizzard watch from Friday afternoon through late Saturday. The National Weather Service is warning of “potential life threatening conditions” due to strong winds and heavy snow. Parts of the Washington, D.C. area could receive up to of 3 feet of snow, putting this storm in the record books and paralyzing travel in the area.
Hurricane Hunters are planning to survey the storm on Thursday while local National Weather Service offices around the U.S. are launching extra weather balloons, all in an effort to gather more data to feed into forecasts in the coming days. The intense efforts underscore just how serious this storm is and fears that it could end up ranking among the biggest and most costly storms to ever hit the region.
While the snow is certainly the most notable and visual phenomenon, parts of the East Coast could also face a major storm surge event that could wreak havoc and up the damage. The fact that the storm is slow moving and showing up during the highest tides of the month means prolonged flooding is possible, particularly around the Chesapeake Bay and parts of New Jersey and Long Island.
The National Weather Service Mount Holly, N.J. office, which covers the Jersey Shore and Philadelphia, is already anticipating a top 5 coastal flood event.
On Saturday, powerful winds in excess of 60 mph could whip up waves that could reach 30 feet. As they come ashore, beaches will take a pounding and face widespread erosion.
Models also show a current storm surge of around 5 feet coming ashore with Saturday’s high tide. In Cape May, N.J., the current forecast high tide mark on Saturday evening would be the third-highest on record while Atlantic City would come in at 10th in the record books, according to Stephen Stirling at NJ.com. That could push water inland and cause widespread property damage.
“Looks like water levels may rise 3-4 feet above predicted non-storm levels at Sandy Hook, Atlantic City and Cape May,” David Robinson, the New Jersey state climatologist, said in an email. “The non-storm levels take into account the astronomical high tide from the full moon, so these are hefty totals. This may challenge past winter storms such as March 1962 and December 1992, but that would be considered worst case scenarios right now. This event will last through several high tides (unlike most tropical systems) but likely not as many as in ’62. Thus if I was to pick an event that it might challenge best it would be ’92.”
Over at Slate, Eric Holthaus warns that this storm could rival the surge from Hurricane Irene in New York, which came within a foot of inundating parts of the city’s subway system. Sea level rise of about a foot in New York has made flooding much more likely, though whether it plays a role in this storm remains to be seen.
And of course there are a number of other factors that play a role in how high waters will go.
“The height of the surge depends on the strength, direction, and fetch of the winds as well as the specific bathymetry (shape of the ocean bottom) and coastline configuration,” Adam Sobel, head of the Columbia Initiative on Extreme Weather and Climate, said. “And the total flooding depends on the peak surge relative to high tide. That is even more uncertain this far out, although if it’s a slow-moving storm then it doesn’t matter as much since the surge could stay high through a couple of tidal cycles.”
One thing that is certain is the costs the winter storm flooding can incur. An ongoing analysis of 53 East Coast winter storms from 2001-2012 by other Columbia University researchers shows that inland and coastal flooding caused nearly 65 percent of all total storm damage.
Future flooding will be even more costly as seas rise, with some research indicating it could cost the world’s biggest cities trillions annually by 2100 unless actions to adapt are taken.
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