Landslide and Mudslide
Landslides, debris flows, and mudslides are fast-moving flows of soil, rocks, vegetation, and debris. They are often triggered by heavy rainfall, saturated ground, earthquakes, or changes to slopes. These events can occur with little warning and move quickly downhill.
How This Affects Alameda County
Landslides and mudslides are most likely in areas with steep terrain, including hillsides, canyons, and creek corridors.
In Alameda County, higher risk areas include:
- Oakland and Berkeley Hills
- Castro Valley and San Leandro Hills
- Niles Canyon and parts of Fremont
- Burned or recently disturbed landscapes
These events are more likely during intense winter storms, atmospheric rivers, or after wildfires where vegetation has been reduced.
Landslides and Mudslides may:
- Occur suddenly with little warning
- Damage homes, roads, and infrastructure
- Block evacuation routes and access to emergency services
- Increase risk near creeks, slopes, and drainage areas
Landslide and Mudslide Safety Tips
Before Storms and Rainfall
- Sign up for AC Alert and local notifications
- Monitor weather forecasts, especially during heavy rainfall
- Know if you live or work in a landslide-prone area
- Plan evacuation routes that avoid low-lying or slide-prone areas
- Keep drainage areas, gutters, and culverts clear
- Avoid building or placing items near steep slopes when possible
During Storms and Rainfall
- Listen to the radio or watch TV for warnings about intense rainfall or for information and instructions from local officials, such as evacuations
- Move to higher ground and away from slopes, if you feel unsafe and if you see a landslide or mudslide starting
- Be alert when driving. Do not drive through debris, flooded roads, or unstable areas
- Avoid creek beds, drainage channels, and steep hillsides
Take action if you are in the path of a landslide or mudslide:
- Leave immediately and move uphill or away from the path of the slide
- Take cover under a desk, table, or other piece of sturdy furniture, if escape is not possible
- Protect your head and body from debris
After Storms and Rainfall
- Listen to the radio or TV for emergency information. Follow public safety and health guidance
- Stay away from the site. Additional slides may occur
- Check on neighbors and those who may need assistance
- Watch for flooding, damaged roads, and unstable ground
- Avoid downed power lines and report hazards to the appropriate authorities
Recognize the Warning Signs
Be alert to changes in your surroundings, especially during or after heavy rainfall.
- Cracks forming in the ground, pavement, or foundations
- Leaning trees, utility poles, or fences
- Sudden changes in water flow, such as muddy streams or increased water levels
- Unusual sounds, such as rumbling or cracking
- Small slides or falling debris
Note: Take action if you notice the above signs.
Landslide and Mudslide Resources
Alameda County Public Works: Provides road closure status
American Red Cross | Landslide Safety & Preparedness Tips : Learn how to be better prepared for and how to respond to a landslide
California Department of Public Health | Landslides and Mudslides: Public safety guidance and health information
National Weather Service | Flood and Storm Alerts: Offers live weather warnings with details
Ready.gov | Landslide Preparedness: Steps to prepare for and respond to landslides
U.S. Geological Survey (USGS) | Landslide Hazards Program: Information on landslide risks and monitoring