Flash Flood — Adair, Iowa

2025-07-20 · near Arbor Hill, Adair, Iowa

Event narrative

At least 6 to 10 inches of water flowing through portions of the Jasper County fairgrounds. Several parked cars and campers flooded.

Wider weather episode

A moist and unstable environment on the southern side of an east-west oriented boundary brought thunderstorms to areas along and south of Interstate 80 in Iowa during the late evening of July 19th, 2025 and morning of July 20th, 2025. Despite 30 to 40 kts of shear, storms generally remained sub-severe as they tracked southward through Iowa. However, upon reaching the southern portions of the state, the storms made an eastward turn towards Wapello county where they encountered drier air in the low levels. Storm intensity began to diminish as the line tracked eastward, but the collapsing system, moving through an environment favorable for strong downdrafts, produced a concentrated burst of damaging winds in Eldon, Iowa. These downdraft winds produced tree damage throughout the town, injuring one person.

As the initial storms weakened and departed southward into Missouri, a stout low-level jet began to strengthen across southwestern and central Iowa, continuing to advect large amounts of moisture and provide lift along the boundary. The resulting storms were slow-moving and efficient rain producers, leading to prolonged residence times and rainfall rates of 1 to 3 inches per hour. This resulted in widespread rainfall amounts of 3 to 5 inches through much of central and south-central Iowa, including within the Des Moines metro.

The torrential downpour quickly overwhelmed drainage systems, leading to ponding water and flash flooding in multiple areas. Law enforcement and emergency management reported ponding water on roadways in multiple towns through Guthrie, Adair, and Madison counties. However, Winterset saw the most extensive flash flooding of areas west of the Des Moines metro. Floodwaters entered homes, rendered roadways impassable within the town, and shut down Highway 92 west of town. Rainfall rates were also intense in the Des Moines area, but impacts were generally limited to localized ponding in low-lying areas. East of the metro in Colfax, IA, heavy rainfall led to flooding at the Jasper County fairgrounds, impacting parked cars and campers. Rainfall generally subsided through the morning, but areas over central Iowa were now primed for a second round of thunderstorms and heavy rainfall expected on the afternoon of July 20th, 2025.

View location on OpenStreetMap → (41.6808, -93.2534)

Source: NOAA Storm Events Database, event_id 1289458. Narrative written by the NWS forecast office that issued the report.