Thunderstorm Wind in Carroll County, Iowa

Large limbs down across the town of Coon Rapids.

On the evening of July 23rd, 2025, a weak wave passed along a southwest to northeast oriented boundary draped over western and northwestern Iowa, increasing convergence and initiating storms within a highly unstable environment. Slow storm motion, resulting from a relatively weak kinematic environment, combined with abundant mid- and upper-level moisture to produce efficient rainfall. Rainfall amounts of 4 to 6 inches were measured in northern Iowa. Minor flooding in low-lying areas occurred, but no significant flash flooding was reported.

This environment, characterized by meager effective shear and heavy rainfall, led to rapid cold pool production and outflows outpacing storms. While this limited the threat of widespread wind damage, sporadic downburst winds occurred with thunderstorms firing along the outflow, resulting in isolated tree damage in the town of Corwith early in the evening. Wind damage was also reported later in the evening as storms moved through Ankeny and Bondurant, damaging trees, shingles, and displacing loose objects in town.

In addition to these downburst winds, an interaction between thunderstorm outflow dropping southward from northern Iowa, and the cold pool with the main wave tracking eastward out of western Iowa produced a small but persistent enhancement of surface winds along their intersection. This resulted in a narrow swath of damaging winds starting near Willey in Carroll County, then tracking east-southeastward through Coon Rapids and south of Bayard and Bagley. Wind gusts of 65 to 75 mph were measured along this swath, resulting in mostly tree damage, as well as damage to one hog confinement near Willey.