Icing Severity in the December 2002 Freezing-Rain Storm from ASOS Data

Abstract

The ice storm of 3?5 December 2002 affected the southern United States from Oklahoma to Virginia. The weight of ice on trees and power lines caused power outages lasting more than a week in some areas. The total precipitation across this region is mapped using data from both Automated Surface Observing System (ASOS) hourly reporting stations and National Weather Service cooperative daily reporting stations. The storm severity is quantified in terms of the equivalent uniform radial ice thickness using data from ASOS weather stations. Estimates of the radial ice thickness are determined by using an algorithm based on a relationship between the frequency drop of the ASOS icing sensor and the measured mass of ice on a horizontal cylinder and by using the hourly aviation weather reports (METAR) in ice accretion models. These estimates are compared and anomalies in the data and anticipated improvements to the ASOS sensors and software are discussed.