Heavy Snow in Iowa, March 18, 2005

A late season snowstorm affected northern Iowa during the day on the 18th, into the evening. Low pressure moved into the northern Rockies on the 17th and eventually tracked east-southeast across Iowa. Moisture was lacking for the system, however dynamics made up for the moisture shortcoming. Surface dew points only rose to the upper 20s to low 30s as the Gulf of Mexico was essentially cut off. A strong south-southwest flow of warm air streamed north over the top of colder air at the surface. Isentropic lift was very impressive. Upward vertical velocities were in the 15 to 30 microbars/sec through the dendritic layer across northern Iowa. Light snow fell during the overnight hours into the early morning of the 18th. Snowfall amounts were quite light however. Heavier snow began to set up during the morning of the 18th. The snow band became convective, resulting in heavy snowfall of 1 to 2 inches per hour at times. The snow piled up quickly with 6 to 12 inch snowfall amounts common across the area. The heaviest snow fell along the Iowa/Minnesota border with most locations receiving a foot of snow. Some of the heavier snowfall amounts included 18 inches in Emmet County at Ringsted and 17 inches in Worth County at Northwood, and 14 inches in Winnebago County at Rake. Travel became difficult and the snow did cause some disruption, however the snow did not cause a major problem in the area. Very little damage was reported with the storm.