Thunderstorm Wind in Lewis County, Idaho

An upper-level low sagging down the Pacific Northwest Coastline was responsible for drawing moist, unstable air northward into Northern Idaho. A combination of surface heating and shortwave energy ejecting from the low triggered strong thunderstorms over Northern Idaho during the afternoon of July 17th. Two thunderstorms that afternoon tracked over a similar stretch of Highway 95 just east of Culdesac. Heavy rainfall from the training thunderstorms, steep terrain, and an overwhelmed culvert were responsible for portions of the hillside at milepost 287, along Highway 95, to washout. These storms also produced wind gusts around 60 mph.