EF2 tornado in Harrison County, Iowa

A tornado developed near Overton Road and 286th Street in Harrison County Iowa. The tornado moved rapidly to the east where it made a direct impact on a home. At this location, the home roof was removed, windows broken, siding ruined, numerous trees snapped, a shed was demolished, and numerous items were thrown up to a half mile downstream. The convergent damage pattern at this location, eyewitness reports of wind direction, along with the 80-yard-wide path of more intense damage gives great confidence that this was a tornado. Winds at this location were estimated at 120 mph based on damage. The tornado moved quickly southeast, causing substantial tree damage with snapped trunks being common along the continued 50 to 100 yard wide track. The tornado moved through neighborhood of acreages along Quentin trail where it snapped many trees but moved in between the homes. The track then became more intermittent for a couple miles before it partially removed the roof of a home along 296th Street and caused additional narrow tree damage for the next two miles. The final damage point that was pretty clearly tornado damage was near 305th and Upton where 3 grain bins were crumpled and blown downstream and a machine shed sustained substantial damage. Beyond this point, the tree damage was sporadic and more evident of the larger scale wind field. Should also note that to the west of this tornado track, there was a debris signature evident on radar, but the damage was much more consistent with a focused downburst or series of downbursts that moved up from the Missouri Valley into the Loess Hills and may have helped to loft light leafy debris. This downburst likely led to the development of the eventual tornado.

A widespread significant damaging wind storm tracked across nearly all of eastern Nebraska and western Iowa on the morning of July 12. These storms produced widespread winds of 60 to 80 mph, with embedded stronger downbursts with wind speeds up to 100 mph. The strongest measured wind gust was 82 mph in Dodge County NE, but some of the high-end straight line wind damage supports embedded wind speeds up to 100 mph.

This storm also produced a few embedded tornadoes. Some of the tornado tracks were only identified by narrow swaths of damage through mature cornfields, with minimal damage otherwise and peak wind speeds similar to the nearby downburst winds. All but one of the tornadoes was preceded by a Wireless Emergency Alert. There were 0 reported injuries or fatalities.