Hail in Montgomery County, Iowa

Emergency management report of hail measured up to 1.75 inches in diameter southwest of Red Oak, IA.

During the afternoon and evening hours of May 16, 2026, severe thunderstorms produced large hail and damaging wind gusts across southwest Iowa. The storms initiated along a frontal boundary draped across the region as a shortwave disturbance pivoted overhead. Earlier in the day, this shortwave had helped develop a surface low near the Colorado/western Nebraska border, which subsequently tracked eastward toward the Mid-Missouri Valley. Ahead of the low, an axis of 2,000 to 3,000 J/kg of MLCAPE developed near the boundary. This instability, combined with increasing deep-layer shear, created an environment highly supportive of strong to severe thunderstorms.

A strong to severe thunderstorm initially tracked across Montgomery County, producing a combination of damaging winds and large hail. The storm initially dropped quarter-size (1.00 inch) hail near Stanton before an Iowa DOT mesonet station 3 miles north of Villisca measured a peak wind gust of 64 mph. As the storm moved over and around Red Oak, reported hail sizes increased. Widespread quarter-size hail within the city quickly gave way to golf ball-size (1.75 inches) hail southwest of town reported by emergency management, 2.00-inch hail measured by a storm chaser to the east-southeast, and baseball-size (2.75 inches) hail reported via mPING just 3 miles south of Red Oak.