MILWAUKEE (CBS 58) -- A National Weather Service damage survey released Wednesday, July 8 found that a Friday, July 3 storm produced peak winds of up to 100 mph as it tracked across Walworth County, with three deaths and 12 injuries reported.

The storm, a high precipitation supercell, moved from southeastern Rock County into Walworth, Racine and Kenosha counties between 11:53 a.m. and 12:32 p.m., according to the NWS. The most severe damage stretched across a path about 26 miles long and up to 5 miles wide, with sustained wind gusts over 60 mph across a broader area.

South of Darien, high winds brought down three empty silos, which fell on a group of motorcyclists sheltering from the storm. Five people were injured by falling concrete.

The storm caused widespread tree damage around Delavan Lake, Lake Como and Lake Geneva, with numerous trees falling onto homes and vehicles. On Geneva Lake, a boat carrying 10 people took on water and sank amid high winds and waves.

The NWS said the damage was consistent with a multi-wave downburst rather than a tornado, describing three distinct wind bursts over a two- to five-minute period, each stronger than the last. A tornado warning had been issued for the area west of Lyons, but investigators found no tornado damage.

The survey also noted five to 10 barns destroyed, thousands of trees snapped or uprooted, and five silos collapsed across the storm's path.