Coastal Change Hazards: Hurricanes and Extreme Storms

Large waves batter the coast of South Kingstown Town Beach, RI during a nor'easter storm in October 2005 (photo courtesy of Bryan Oakley). [larger version]

Extreme Storms

Northeasters (Nor'easters)

A northeaster is a winter storm that forms in the mid-latitudes between the months of September and April. Like a hurricane, a northeaster is a cyclonic storm system, with winds circulating counter-clockwise around a low pressure system. However, the wind speeds associated with a northeaster seldom reach hurricane intensity. Northeasters travel northward in the Atlantic Ocean, with winds blowing from the northeast towards the shore along the eastern United States and Canadian coastlines.

Because of the cyclonic nature of the storm system, the winds blow in a northeastward direction, affecting long reaches of the coastline while the storm is still far to the south. Northeasters tend to be very large and move slowly, generating high waves that attack the shoreline for long periods of time. The onshore directed winds accentuate the incoming tide, while confining the excess water at the shoreline during a low tide stage. Because northeasters move slowly, several tidal cycles can be affected, creating a large coastal storm surge.

Although northeasters are generally not as intense as hurricanes, their slow movement can cause damage to large areas of the coastline. One of the most destructive storms ever experienced in the Mid-Atlantic States was the Ash Wednesday storm of 1962. With wind speeds measured at 60 mph, this storm lasted five tidal cycles, causing damage to more than 600 miles of shoreline. The infamous "Perfect Storm," also known as the 1991 Halloween Northeaster, was a strong northeaster fueled by Hurricane Grace and the Gulf Stream current. Storm winds eventually reached 69 mph, causing $1 billion dollars in damage along the northeastern United States and Canadian coastlines.

return to Extreme Storms Overview | continue to El Niño