Nor’easter to Slap East Coast With Floods, High Winds

A powerful nor’easter will roar up the East Coast Friday, putting more than $468 billion of real estate at risk from coastal flooding, dropping heavy snow in some areas and raking the region with wind gusts that could topple trees and power lines.

While upwards of a foot (30 centimeters) of snow may fall across interior New York, Pennsylvania and northern New England, the storm’s most dangerous aspects will likely be the high tides and winds due to start early Friday and continue through Saturday. Hurricane-strength winds could even strike the waters around Cape Cod in Massachusetts. Gusts of up to 65 miles (105 kilometers) per hour may reach inland areas.

In January, a powerful storm drove tides in Massachusetts to their highest on record, flooding parts of Boston as well as its northern and southern suburbs. The approaching nor’easter could be more destructive because it will move much more slowly than some previous systems, said Rob Carolan, owner of Hometown Forecast Services in Nashua, New Hampshire. Its progress will be blocked by other weather patterns, preventing it from slipping quickly away into the Atlantic.

“It is going to be severe” Carolan said. “There is a high likelihood of those areas that flooded earlier this winter doing it again and doing it for a longer period.”

Tides could rise 3 feet higher than normal in Jamaica Bay in Queens and along southern Long Island, and by as much as 4 feet along the Massachusetts coastline, including Boston Harbor. Waves higher than 20 feet could crash into coastal towns north and south of Boston and on Cape Cod, washing out roads, damaging homes and leaving people stranded “for an extended time,” the National Weather Service said.

The Massachusetts Emergency Management Agency has urged residents along the coast to come up with evacuation plans before high tide on Friday. Coastal flood warnings, watches and advisories stretch along the New Jersey coast and as far south as Virginia. More than 1.2 million homes worth more than $468 billion are at risk from coastal flooding in 11 states from Maine to Virginia, according to the Insurance Information Institute in New York.

Several storms this winter have caused more flooding than usual due to slightly different tracks, sharper differences between cold and warm air masses and because there’s more moisture in the atmosphere, said Patrick Burke, a senior branch forecaster for the U.S. Weather Prediction Center in College Park, Maryland.

The latest storm is being strengthened not only by the sharp gradient of warm and cold air but also record warm spots in the Atlantic. The same thing happened in January, when a winter storm underwent a process known as bombogenesis, with its central pressure – a measure of a its power – dropping 21 millibars in six hours.

Burke said this week’s looming system could become a “bomb cyclone” on Friday, too.