Ice Storm in Iowa, January 1, 2005

A strong frontal boundary was located east-northeast to west-southwest across central Missouri during the early morning hours of the 1st. Low pressure moved northeast along the front as the front lifted slowly north into Iowa by the evening. Very warm air was located south of the front with temperatures warming into the 50s and 60s, along with dew point readings in the 50s. Temperatures at 850 mb over the south half to three quarters of Iowa rose to +9 C. Surface temperatures to the north of the front were generally in the 20s and did not warm above freezing as the front lifted north. Low level winds of 40 to 50 kts pushed warm and moist air over the cold dome, producing freezing rain over much of Iowa. At the onset, all of the precipitation was in the form of freezing rain. Much of the south half of Iowa saw temperatures warm above freezing during the day. A glaze of a few hundredths of an inch to a tenth of an inch or so was common over all of the CWA. Heavier rainfall occurred over the north and northeast sections of the CWA with reports of one quarter to two thirds of an inch of icing. Travel was difficult as the rain adhered to the road surfaces quite easily with surface temperatures in the 20s.