With the IEM receiving the data of severe Thunderstorm and tornado warnings back to 1986 from the NWS, it is worth a look at what counties (pre and post polygon era) has had the most tornado warnings issued in the state since 1986. NOTE: This does include the polygon warnings (2007-Present) which only includes parts of said county as well as County Based Warnings (up to 2006). This dataset includes that part of a county as a whole for this reference.

According to the data, the most tornado warned counties are in western Iowa along the Missouri River, with a few in central Iowa and a cluster of counties in eastern Iowa. (Jones County being the only county in the east in the top ten at #4)

An interesting note as well, Jones and Linn Counties have had a tornado warning issued for either all or part of said county every year since 1995! That’s 15 years in a row and going for 16 this year. Hopefully the string is broken this year with no tornado warnings.