Thursday, November 12, 2009

What do you think of this storm? Virginia and much of the mid-Atlantic coast is experiencing a Nor'easter today: heavy rain, gale force winds, coastal flooding, downed trees, power outages, beach erosion... well, you catch my drift. The storm gets the name Nor'easter because the wind blows primarily from the northeast. A Nor'easter is a cyclone, or low pressure system, whose center stays just off the coast. Nor'easters can have winds of hurricane force and can sometimes intensify very quickly.
This particular storm began as hurricane Ida, a tropical cyclone. Tropical cyclones form over very warm ocean waters and get their energy from the release of latent heat when water vapor condenses into water droplets. They have a warm core, no fronts associated with them and have their strongest winds near the surface. Extra-tropical cyclones get their energy from temperature gradients, such as when a warm air mass collides with a cold air mass. They have a cold core, usually both warm and cold fronts associated with them and have their strongest winds in the upper atmosphere. Tropical cyclones can "morph" into extra-tropical cyclones and vice versa, although the latter is more rare.
Many of the worst blizzards in the Northeast US were Nor’easters. Extreme cold often follows in the wake of a Nor’easter, due to cold air being dragged out of Canada by strong northwest winds behind the storm.
The book and movie The Perfect Storm was about an actual 1991 Nor’easter that absorbed Hurricane Grace and later moved far enough south to become a hurricane itself. Unlike most hurricanes, this storm was never named, and New Englanders still refer to it as the No-Name storm.
Did you know surfers love Nor'easters? Waves can be very high during these storms. Even though it is cold, they just don their wet suits and head out.
Do you have a Nor'easter experience? Here's one of mine: my brother had rented a house in the Outer Banks one spring when a Nor'easter hit. Large quantities of sand blew onto and covered the road near Rodanthe. The highway department managed to open a one-lane track for cars to pass, necessitating a wait for oncoming traffic to clear. In the 30 minutes we were waiting, huge hunks of wet sand were raining down on our car. By the time we arrived at the house, the entire left side of the car was caked in sand. That night the house rocked us like we were in a cradle. It was an experience I will never forget.

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