Synoptic and mesoscale structure of a severe freezing rain event: the St. Valentine's day ice storm

Abstract

A severe freezing rainstorm produced as much as 4.5 cm of freezing rain during an 18-h period at Champaign, Illinois, on 14-15 February 1990, resulting in over $12 million in damage, week-long power outages, and a federal disaster declaration. The ice storm occurred during the University of Illinois Winter Precipitation Program based in Champaign. The early mesoscale evolution of this storm was documented for several hours with a 10-cm Doppler radar and Cross-chain Loran Atmospheric Sounding System soundings launched every 3 h. The freezing rain event occurred when convective bands developed over a slow-moving warm front during a period of strong overrunning. The strongest convection developed in a period of about 1 h, with a narrow elongated band northwest of the radar producing very heavy sleet and a band just south of the radar producing heavy freezing rain, along with in-cloud lightning. -from Authors