As the rain water erodes the hillsides and canyons, it collects at the bottom and creates not only a powerful water flow, but a debris flow as well, which accelerates more erosion and intensifies that force of the flow, until it eventually spreads out over a flat area such as a road, parking lot, field, or becomes impounded in a basin or flows into the river. However when these cells drop intense rain in the foothills we will see what occurred (like) on Saturday.”Īs rain is dropped on the hillsides, it collects into the canyons that brings loose soil and rocks along with it, Cooley said. “If it occurs in the bottom of the valley, we will experience drainages being overwhelmed which will cause localized street flooding and some flows onto properties and sometimes into businesses or residences. “The issue is where a cell drops an intense amount of water,” Cooley said. According to Deputy Public Works Director Rick Cooley, the mudslide that occurred in the area of the Fandango, as well as a slide that occurred at the same time on Goni Road, are typical of thunderstorms with heavy rains in the foothill areas of town.
