Natural Hazards - Landslides

Landslides occur and can cause damage in all 50 States. Severe storms, earthquakes, volcanic activity, coastal wave attack, and wildfires can cause widespread slope instability. Landslide danger may be high even as emergency personnel are providing rescue and recovery services.

To address landslide hazards, several questions must be considered: Where and when will landslides occur? How big will the landslides be? How fast and how far will they move? What areas will the landslides affect or damage? How frequently do landslides occur in a given area?

Answers to these questions are needed to make accurate landslide hazard maps and forecasts of landslide occurrence, and to provide information on how to avoid or mitigate landslide impacts.

The U.S. Geological Survey develops methods to answer these questions to help protect U.S. communities from the dangers of landslides.

USGS Landslides Hazard Alerts

Flash Flood Warning for the Santiago Fire in Orange County
At 10:14 AM, December, 15, 2008, the National Weather Service in San Diego issued a Flash Flood Warning for the area burned by the Santiago Fire in Orange County California. Areas potentially affected by this warning include the area burned by the 2007 Santiago Fire, Silverado Canyon, Fremont Canyon, the towns of Silverado and Modjeska, and the cities of Tustin Foothills, Tustin, and Mission Viejo. Debris flows issuing from burned basins can impact roads travelling up Silverado Creek, Williams Canyon, Harding Canyon and Modjeska Creek.
Flash Flood Warning for Southwestern San Bernardino, North-Central Orange, and Northwestern Riverside Counties in Southwest California
At 6:30 AM, December, 15, 2008, the National Weather Service in San Diego issued a Flash Flood Warning for the area burned by the Freeway Complex. Areas potentially affected by debris flows are Olinda Village near Brea, Carbon Canyon, Brush Canyon, Box Canyon and San Antonio near Yorba Linda, and the Cascade apartments in Anaheim. Residents and motorists in, and below the recently burned areas should be alert to debris flows that may block roads and culverts.