Winter Storm in Iowa, February 14 to 15, 2003

The seasons first major winter storm moved into Iowa during the day on the 14th. Low pressure moved into the southwest U.S., then across the Rockies. By the morning of the 14th, the low pushed into southwest Kansas into the Oklahoma Panhandle area. The eventual track was not typical of major snow storms in Iowa as the low tracked straight east, then eventually southeast into Alabama and Mississippi. A very wide contrast was in place between Arctic high pressure to the north and the storm to the south. For the first time in many months, this storm system had ample moisture to work with as surface dew points in the low 60s spread as far north as eastern Kansas and central Missouri. Meanwhile, north east of Iowa, where the surface flow was from, temperatures were in the -25 to -40 degree F. range over western Ontario. Precipitation spread into the state during the early morning hours of the 14th. The warm air had the upper hand initially, with the precipitation falling in the form of light rain over the south half of the state into the morning. As northeast winds strengthened, cold air was drawn down at the surface with the rain gradually changing to freezing rain and sleet from the north. Areas north of U.S. Highway 20 saw only snow with amounts in the 2 to 5 inch range. South of that, as the precipitation changed to freezing rain, many area received one to two tenths of an inch of freezing rain and sleet before the snow began. The heaviest ice accumulation was in Ida and Crawford Counties. A few area between Holstein and Schleswig received close to one quarter of an inch of ice. Some tree branches fell as a result of the ice accumulation. The changeover from to snow was slow, with the southern border of the state not changing over to snow until after midnight on the on the morning of the 15th. Once the snow began, it fell quite heavily. Snowfall rates of around an inch per hour were common. The heaviest snow fell across central Iowa, where a convective band of heavy snow developed. Snow in this band was falling at the rate of 1 to 2 inches per hours, with several reports of lightning and thunder received in the area around Des Moines. As for snow amounts, a broad area received in excess of 6 inches of snow. North of U.S. Highway 30, snowfall was generally in the 6 to 8 inch range. Much of it fell in under 10 hours during the beginning of the event. A few heavier reports were received, such as Dayton in Webster County with 9.5 inches and 8.5 inches in Rhodes in Marshall County. Southern Iowa south of U.S. Highway 34 generally received 6 to 10 inches of snow. Some of the heavier snow fell in the Ottumwa area of Wapello County with around 10 inches reported. The area between U.S. Highway 34 and U.S. Highway 30 received the greatest snowfall as the convective band of heavy snow remained over this area. Snowfall amounts in this band were generally in the 8 to 12 inch range. The heaviest snow was in the greater Des Moines area due to thunderstorm activity. Grandview Park, on the east side of Des Moines, received the most with 14 inches. The Des Moines Airport received 13 inches, as did other parts of the east side of Des Moines. Windsor Heights picked up 12.3 inches, while Pleasant Hill and Alleman each received 12 inches. Due to the initial precipitation falling in the form of freezing rain and sleet, then a heavy wet snowfall on top of that, travel conditions deteriorated very rapidly. Though roads did not become impassible, however travel did become quite difficult. Gusty northeast winds of 20 to 40 MPH caused considerable drifting of the snow and some blowing snow. Had it been a drier snow, the situation would have approached blizzard conditions. The heavy snow and icing resulted in the closure and postponement of most activities scheduled for the night of the 14th and the 15th. Conditions improved once the storm moved out late on the 15th, however the improvement was slow because of the heavy wet nature of the snow.