Granite Falls, MN Hail Storm – July 2025

What Happened

A severe hail storm moved through Granite Falls, Minnesota, on July 19, 2025, and produced spotter-verified hail up to 1.75 inches. The storm remained active from early evening into the overnight hours, with repeated hail detections and ground reports tied to the same corridor.

NWS alerts first flagged 1.5-inch hail at 7:28 PM CDT and again at 7:43 PM CDT, both backed by dual-polarization radar. By 7:51 PM CDT, hail estimates eased to 1.25 inches, then rose again to 1.25 inches at 8:12 PM CDT. A spotter-verified report at 8:05 PM CDT put hail at 1 inch.

The strongest run of reports came later in the evening. At 9:01 PM CDT, radar and spotter input supported 1.25-inch hail. Ten minutes later, at 9:11 PM CDT, a spotter-verified report documented 1.75-inch hail. Another spotter report at 9:10 PM CDT placed hail at 1 inch. A pair of overlapping reports at 9:28 PM CDT described most stones between quarter and half dollar size, with several golf ball to hen egg sized, and one observer used a key to measure 1.1 inches across the black portion.

Radar support remained steady after that. Alerts at 9:27 PM CDT and 10:50 PM CDT showed 1-inch hail on dual-polarization radar. Spotter-verified hail of 1 inch returned at 10:03 PM CDT and 10:13 PM CDT, with another 1.75-inch report at 10:13 PM CDT. The storm stayed organized into the night, with 1.75-inch radar confidence at 10:39 PM CDT, followed by 1.25-inch hail at 11:11 PM CDT and 1-inch hail at 11:51 PM CDT.

Overnight alerts continued at 1:25 AM CDT, 1:56 AM CDT, and 5:25 AM CDT, with dual-polarization radar maintaining hail detection between 1 and 1.25 inches. Field notes also included a report at 10:28 PM CDT of a rotating wall cloud with a brief funnel cloud, alongside a separate spotter note at 9:26 PM CDT of flooding roads around Marshall.

Damage Assessment

The field reports point to concentrated hail impacts in and around Granite Falls, with the heaviest verified stones reaching golf ball to hen egg size. Reports at 9:28 PM CDT described a mix of quarter- to half-dollar hail with larger stones mixed in, and the 9:11 PM CDT spotter report confirmed 1.75-inch stones on the ground.

The damage picture is consistent with a storm that produced repeated stone size changes across the evening, not a single brief burst. Radar-based alerts held in the 1-inch to 1.75-inch range for hours, while spotter reports showed the hail reaching larger sizes during the more intense part of the event. That kind of overlap usually means a broader swath of roof, siding, and vehicle exposure across the warning area, especially where the strongest cells repeated over the same streets.

The road flooding report near Marshall adds another layer to the event. It shows the storm was not limited to hail alone. Heavy rain and poor drainage were present in the same broader system, and that can complicate post-storm inspections in low-lying areas and along rural routes.