WINTER WEATHER AWARENESS WEEK - ICE STORMS

Blog Post By Brian Neudorff:

October 25th through the 31 is Winter Weather Awareness Week in the state of New York. Yesterday we featured the topics from the National Weather Service on preparedness and heavy snow. Today the topic is on ice storms.

In the short time I've been here there is one thing that gets a lot of response and questions from viewers and that is when you mention the possibility of ice. Ice storms can be very damaging as Rochester experience back in 1991.

Written by: National Weather Service in Buffalo

Ice storms are one of winters most dangerous hazards. Heavy accumulations of ice can bring down trees and power lines as well as topple utility poles and communications towers. This can disrupt power and communications for days or even weeks while crews repair extensive damage. Even small accumulations of ice can be extremely dangerous to motorists and pedestrians. Bridges and overpasses are particularly dangerous because they freeze before other surfaces.

Freezing rain is the result of a temperature inversion which forms in the atmosphere. Rain falls in the warmer air well above the surface. However if temperatures are below freezing at the surface, the rain freezes on impact with objects and creates a coating of ice. A thick layer of ice adds tremendous weight to objects such as trees and power lines causing them to break under the stress. Even thin layers coating road surfaces are hazardous since they are very slippery.

Unfortunately, New York experiences some of the highest frequencies of freezing rain nationwide. Warm air blowing from the south is frequently deflected aloft the mountains, trapping the cold air in the valleys.

A couple of major ice storms over the past decade also rank as among the worst in history. In 1991, an ice storm struck western and northern New York from Jamestown to Watertown. In all, 20 counties were affected, 13 of them under a federal disaster declaration. Rochester was especially hard hit with schools and many businesses closed for a week. Once again, thick ice accumulations from freezing rain knocked out power. In all, almost 325,000 customers were without power. It was the costliest storm ever to strike New York State, exceeding the destruction caused by tropical storm Agnes.