The Local Winter Storm Scale: A Measure of the Intrinsic Ability of Winter Storms to Disrupt Society

Abstract

A local winter storm scale (LWSS) is developed to categorize the disruption caused by winter storms using archived surface weather observations from a single location along the U.S. East Coast. Development of LWSS is motivated by the recognition that the observed societal impact from a given winter storm (called realized disruption here) arises from the convolution of two factors, the meteorological conditions that lead to disruption (i.e., intrinsic disruption) and society's susceptibility to winter weather. LWSS is designed to measure the first factor, intrinsic disruption. The scale uses maximum sustained winds, wind gusts, storm-total snowfall and icing accumulations, and minimum visibility to arrive at a categorical value between 0 and 5 inclusive. An alternate method is used to quantify the realized disruption that each storm produced and helps calibrate aspects of LWSS. All winter storms observed at Newark Liberty International Airport over the 15 cold seasons between 1995/96 and 2009/10 were categorized using LWSS. Focusing on one location reduces the variability in societal susceptibility, which allows the relationship between intrinsic disruption and realized disruption to be quantified. Some important factors related to societal susceptibility were found to increase storms' realized disruption, including occurrence during a weekday, off-peak season, and less than two days subsequent to a previous storm. A closer examination of the 9–11 February 2010 winter storm demonstrates LWSS's ability to depict the spatial variability of the storm's intrinsic disruption. This information is used to infer variations in societal susceptibility between metropolitan areas and reveals the need for an instantaneous intrinsic disruption index to account for temporal variations in storm intensity.