Winter Storm in Union, Iowa

A deepening upper level trough pushed across Iowa from the evening of the 11th through the 12th. Precipitation began on the leading theta e advection wing, followed by more board forcing overnight and through the 12th. With deep moisture, a deep dendritic growth zone, and periods of super saturation, and cold temperatures in the single digits to teens at the surface, snow ratios of 18 or 20 to 1 were observed. Central and southern Iowa received a widespread 3+ inches of snow, with a band of 6-10 inches across central to southeast Iowa. This event resulted in a number of accidents on roads across central and southern Iowa, including a large multi-vehicle accident involving at least 9 vehicles.

Key Impacts: transportation delays, traffic accidents.