Grantsville, UT Hail Storm – September 2026

A severe hail storm tracked through Grantsville, Utah on September 22, 2026, producing stones up to 1.95 inches and triggering multiple NWS hail alerts from mid-afternoon into early evening. The event combined repeated dual-polarization radar detections with spotter reports inside the Grantsville metro.

What Happened

Radar first identified hail-producing signatures near Grantsville in the mid-afternoon. NWS hail alerts began at 2:17 PM MDT (20:17 UTC) with radar indicating roughly 1.00-inch returns. A stronger pulse appeared around 3:25 PM MDT (21:25 UTC) when radar-derived estimates increased to about 1.70 inches. Subsequent alerts at 4:05 PM MDT (22:05 UTC) and 4:11 PM MDT (22:11 UTC) showed repeating 1.00-inch radar signals as the storm persisted through the late afternoon.

Field observers using mPING reported quarter-sized hail in Grantsville at 4:13 PM MDT (22:13 UTC). Two independent mPING submissions matched the same time window and locality. The radar continued to detect hail echoes into the early evening, with later alerts at 5:37 PM MDT (23:37 UTC) and 6:29 PM MDT (00:29 UTC) indicating additional pulses of mixed-size returns.

The sequence shows a multi-pulse storm that produced intermittent stronger cores embedded in a broader hail-producing circulation. Dual-polarization radar provided repeated hail detections along the storm track, while spotter reports verified hail at the surface during the late-afternoon core near Grantsville.

Damage Assessment

Field reports for this event were limited to two spotter-verified mPING submissions recording quarter-sized (1.00 in.) hail at 4:13 PM MDT (22:13 UTC) in the Grantsville area. Those ground reports are the primary surface evidence captured in public submissions for this storm.

Radar indicated periods with larger hail aloft, but submitted local spotter observations did not include larger stones or documented structural damage in the provided reports. There were no spotter-attested reports of vehicle dents, broken skylights, or roof penetration in the public field reports associated with these Grantsville submissions.

Given the mixed radar signature and the timing of the spotter reports, surface impact appears concentrated in a late-afternoon window near the reported mPING locations. Any roof, vehicle, or exterior material stress is most likely along that localized path and where radar later indicated renewed hail echoes in the early evening.

What Contractors Should Know

Inspect roofs and soft metals first in the immediate Grantsville metro and along the late-afternoon hail path identified by observers. Start with areas exposed on the windward side and valleys in roof geometry. Quarter-sized impacts can bruise asphalt shingles, dent metal flashing, and abrade solar panels over time; document granule loss, dents, and hairline fractures with date-stamped photos.