EF1 tornado in Pottawattamie County, Iowa

The tornado started just south of the County Road 18 to the west of the city of Avoca, Iowa. The tornado tracked to the north northeast through open fields initially. Due to the recent harvest the tornado was easily tracked through the fields due to ground scouring of the left-over corn stocks. The tornado narrowly missed a farmstead along 420th street but did destroy one empty grain bin located across the street from the farm. The tornado continued to track across open fields until it crossed the busy Interstate 80 where a semi was lofted and tossed into a ditch on the north side of the interstate. At this location there were also large hardwood trees that were uprooted. The tornado continued to the northeast into Shelby County.

A powerful upper level low pressure system moved quickly across the central Plains during the day on November 11th. As low pressure moved from Kansas into eastern Nebraska during the day, warm and moist air was pushed northward into the region. This unseasonably warm and moist air led to increasing instability during the afternoon over western Iowa and southeast Nebraska. This combined with the strong wind field associated with the low produced an atmosphere ripe for severe weather. Thunderstorms developed along the cold front in eastern Nebraska by early afternoon, and then increased in coverage and intensity as they tracked east into western Iowa during the early afternoon. Large hail and isolated tornadoes were produced by these thunderstorms.