The remainder will be released in September 1998. For the complete schedule, see the index map below. Mudslides are common in the rainy season through-out California where slopes are steep. In arid southern California, frequent wildfires contribute to instability by removing vegetation that helps stabilize the soil. Debris avalanches move at speeds exceeding 10 mph.
Debris flows move more slowly.
Most fairly steep slopes have enough soil and loose rock for potential mudslides. To be safe, assume that all drainages in steep, hilly, or mountainous areas are capable of carrying debris flows, especially if relatively loose, sandy soils are present in the watershed. Minimize the risk of mudslide damage by avoiding building sites at the bottoms and mouths of steep ravines and drainage courses. The geologic review is a critical part of the evaluation process of a proposed development. It is the responsibility of the reviewer to ensure each geologic investigation and the resulting report adequately address the geologic conditions at a given site.