Kevin Walters
10-13-2009, 02:08 PM
A late season tornado outbreak in Iowa included a killer F5 tornado that struck Belmond. Strong surface low, very steep mid level lapse rates, and moderate directional wind shear combined to produce at least twelve tornadoes across Iowa. Having extreme instability present over Iowa at this time of year does happen occasionally. As the surface low moved into Western Iowa a warm front retreated to the North as 70 degree dew points surged in. Surface winds in Nothern Iowa backed nicely as breaks in cloud cover pushed temperatures into the upper 70's and low 80's. Thunderstorms developed in the early afternoon and raced to the NE. The thunderstorm that produced the F5 tornado developed just NE of the triple point where backed surface winds were optimal. The tornado struck Belmond at 2:55 PM just minutes after the home coming parade ended. Damage was extensive throughout town, 6 people died and over 170 were injured. Many farms suffered damage along the tornado's path, at least three were completely leveled. As the surface low wrapped up and moved to the NE, Sioux City Iowa received four inches of wet snow.