A case study of a Great Lakes supercooled large droplet icing cloud

An analysis of both the large and small-scale structure of a SLD icing cloud is presented. The NASA Glenn Twin Otter research aircraft sampled the cloud on 26 January 1998 and collected both state and microphysical data. Freezing drizzle was found within a cloud layer having supercooled liquid water content up to 0.4 g/m^3. This created a significant SLD ice accretion on the aircraft, with ice well aft of the deicing boots.

A lake effect cloud formed along the west side of Lake Michigan, and interacted with a synoptic scale overrunning air mass to produce the SLD icing condition. The subfreezing cloud depth ranged from the surface to 12,000-ft. Three distinct icing layers were identified within the cloud, with the middle layer shown to initiate the SLD production. This analysis provides the icing and cloud modeling community with a detailed depiction of the structure of a dangerous SLD icing cloud.