Flash Flood in Johnson County, Wyoming

The last in a series of thunderstorms on Wednesday, June 3, brought very heavy rain to Buffalo and the surrounding area. The ASOS at Johnson County Airport measured 0.98 inches of rain in less than 25 minutes as the storm moved north and then stalled over Buffalo. The ASOS recorded a grand total of 1.26 inches in less than one hour. Saturated soils were unable to absorb the rain which quickly ran through the streets of Buffalo and filled area creeks. Five Buffalo homes were declared destroyed, and the senior center and BLM office sustained flood damage. Some reports indicated water four feet deep in low-lying areas. The water was running fast enough to lift and carry the top layer of pavement on a couple of Buffalo streets. A few county roads and some private bridges were washed out due to culvert failures as a result of the raging flood waters.

The combination of a stalled frontal boundary, jet streak dynamics, and an upper level disturbance sweeping across Wyoming created the conditions necessary to produce severe thunderstorms in central Wyoming. A moisture-laden atmosphere also set the stage for flash flooding. Johnson County took the brunt of the heavy rainfall and flash flooding on Wednesday evening, June 3. Both the city of Buffalo and Interstate 90 were severely impacted by flood waters. Roads were closed, homes damaged or destroyed, and at least a few public buildings damaged. To the south and west, there were multiple reports of large hail in Fremont and Natrona counties.