Paul J. Kocin The Weather Channel 300 Interstate North Parkway Atlanta, GA 30329

Louis. W. Uccellini NOAA/NWS National Centers for Environmental Prediction 5200 Auth Road Camp Springs, MD 20746

Abstract

A Northeast Snowstorm Impact Scale (NESIS) is presented to convey the impact of snowstorms in the Northeast Urban Corridor that extends from southern Virginia to New England. The scale is similar in concept to other meteorological impact scales (ie., the Fujita and Saffir-Simpson scales; Fujita 1971; Saffir 1977), but differs in that the primary focus is on areal coverage and population affected by heavy snowfall, rather than the potential for wind-related damage (and storm surge for Saffir-Simpson) implicit in other scales. Furthermore, the NESIS is designed to provide a simple, direct integrated measure of storm snowfall and distribution for a given storm, quantifying a snowstorm in a way easily communicated to the public. It does not provide a categorized ranking since values ranged between 0 and 8 for 30 cases. It also does not provide an instantaneous measure of storm intensity for a local area (Zielinski 2002).

The primary components of the scale are snowfall amounts (greater than 10 inches or 25 cm; in 10-inch or 25-cm increments), areal extent of the snowfall and population density (normalized to the 1999 census). The NESIS is applied to the 30 cases of the most crippling snowstorms that affected the NE Urban Corridor from 1950 to 2000, 30 additional cases of snowstorms that either produced more moderate snowfall amounts or which affected inland areas, and 5 historic cases between 1888 and 1950 (Kocin and Uccellini 2002 a,b). From the 65 examples considered, five storms stood out with the highest values, scoring between 5 and 8 ; the Blizzard of January 1996, the Superstorm of March 1993, the March Blizzard of 1888, the November 1950 cyclone and the Blizzard of February 1899.