Examples from California illustrate typical responses to erosion and debris flow disasters in the United States. Political institutions leave virtually all responsibility for disaster prevention to the lowest levels of government or to individuals. Three circumstances in which disasters occur are discussed : urbanized debris cones, urbanized unstable landforms, and logging of unstable terrain. By far the greatest economic losses result from the urbanization of unstable landforms. These losses occur not because of a lack of appropriate mitigative technology but as a result of the reluctance of local governments to impose effective land use controls. Although logging-related erosion and debris flows receive much public attention, the associated costs are slight in comparison to other disasters, in comparison with other natural disasters, funds devoted to landslide research are much less than warranted by associated economic costs and loss of life.