Winthrop, IA Hail Storm – July 2025

What Happened

A severe hail storm moved through Winthrop, IA, on July 11, 2025, producing verified 1.5-inch hail and repeated spotter reports of tree damage and heavy rainfall through the afternoon and evening.

The first hail alerts came late in the morning, when dual-polarization radar flagged 1-inch hail at 11:27 AM CDT. Activity strengthened around 2:54 PM CDT, when radar-supported hail estimates reached 1.25 inches, then gained spotter support minutes later at 2:58 PM CDT. By mid-afternoon, the storm was producing a more organized hail signal across the Winthrop area.

A second round of stronger alerts arrived after 4 PM. At 4:16 PM CDT, radar again detected 1-inch hail. Ten minutes later, spotter verification backed that estimate. At 4:39 PM CDT, dual-polarization radar reached 1.5 inches, the peak confirmed hail size in this event. Spotter-verified 1-inch hail followed at 4:47 PM CDT and continued through the evening, with additional verified reports at 5:01 PM, 5:05 PM, 5:49 PM, 6:03 PM, 6:11 PM, 6:27 PM, 6:46 PM, 6:58 PM, and 7:41 PM CDT.

Field reports during the storm matched the broader hail sequence. At 5:50 PM CDT, a spotter reported hail occurring in real time. By 7:19 PM CDT, an automated gauge had recorded 1.18 inches of rain in one hour. Additional reports at 7:36 PM CDT placed rainfall since 4 PM at 2.29 inches, and by 8:07 PM CDT the total rainfall had reached 2.5 inches.

Damage Assessment

The field reports point to a storm that did more than drop hail. Spotters reported 1 to 2 inch tree limbs down at 5:09 PM CDT, followed later by reports of several trees and power lines down across the county. Another report at 8:07 PM CDT described 2 inch diameter tree limbs down. The damage notes are consistent with scattered wind and hail impacts across the broader Winthrop area.

Rainfall was a separate issue. The 1.18-inch hourly gauge reading, then the 2.29-inch total since 4 PM, and the 2.5-inch total by 8:07 PM CDT show a storm with prolonged heavy rain behind the hail core. That rainfall rate can add cleanup time even where hail impact was limited.

The hail reports themselves stayed concentrated around the 1-inch to 1.5-inch range, with repeated verification through the late afternoon and early evening. That pattern suggests multiple hail bursts rather than a single short pulse. Contractors should expect isolated roof, siding, gutter, and window claims rather than uniform loss across every property in the city.

Tree debris deserves attention first. Limb failures and power line reports usually leave more visible exterior evidence than hail alone. Crews should document tree strikes, screen for punctures in soft metals and shingles, and check for collateral damage where limbs hit roofs, fences, detached garages, and vehicle cover.

Winthrop, IA Hail Storm – July 2025

NWS WARNING AREAS · 48

What Happened

Damage Assessment

What Contractors Should Know

Storm Details

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