Flat Rock, IL Hail Storm – May 2026

A severe hail storm crossed Flat Rock, Illinois on May 16, 2026, producing 2.33-inch stones and an extended radar-detected hail swath during the afternoon and early evening.

What Happened

The event began with scattered noontime activity and intensified in the late afternoon. NWS warnings and radar-derived hail detections were issued repeatedly through the day, a total of 38 alerts spanning morning into early evening. Radar-derived signatures showed intermittent cores moving northeast through the metro between mid-afternoon and early evening. Around 3:40 PM CDT, Crawford County emergency management logged several public reports of quarter-size hail. Late-afternoon radar returns produced larger returns and multiple near-storm spotter confirmations. A residential report arrived at 4:55 PM CDT documenting quarter-size stones. Spotter-verified reports continued into the early evening, including downtown Louisville around 5:15 PM CDT and a nickel-size report in Simpsonville, KY at 5:55 PM CDT. The combined record includes NWS warning-only alerts, dual-polarization radar detections, and spotter-verified observations that tracked the cells across multiple counties.

Damage Assessment

Field reports and radar returns indicate primarily small-to-moderate surface impact along the reported path. Crawford County public reports around 3:40 PM CDT described consistent quarter-size hail across multiple public locations. A residential report at 4:55 PM CDT referenced accumulation on vehicles and landscaping in a specific neighborhood. Downtown Louisville accounts at 5:15 PM CDT noted quarter-size hail across several blocks, with observers reporting hail on sidewalks and streets. A 5:55 PM CDT public report in Simpsonville, KY described nickel-size stones. These ground observations align with radar-detected hail cores that passed over populated corridors. There are no broad structural collapse reports in the field notes. Reported impacts were localized to vehicle panels, roof shingles, siding, and exposed landscaping where quarter-size to nickel-size hail was observed. Timing of the most concentrated activity was late afternoon into early evening, concentrated along the corridor identified by repeated radar detections and spotter calls.

What Contractors Should Know

Inspect vehicle fleets and surface-mounted equipment first in the areas with spotter-verified reports. Start with locations tied to the Crawford County 3:40 PM CDT observations and the downtown Louisville 5:15 PM CDT report. Expect hail-related dents on vehicle roofs, hoods, and aluminum trim. Photograph all damage in place and log the exact address and time of the report for claims and routing.

For roofing contractors, prioritize shingle lift, bruising, and granule loss at residences reported at 4:55 PM CDT and along the radar-identified swath. Use close-range inspections and medium-format photography to document hail impact angles. Look for clustered impact patterns consistent with quarter-size and nickel-size hail rather than widespread panel failure. For siding and gutter crews, check for punctures, cracked vinyl, and bent gutters in the same neighborhoods.