Landslides and debris flows

Habitat Ready: Disaster preparedness for homeowners

Landslides and debris flows are caused by a number of factors, such as earthquakes, heavy rain, volcanic eruptions and poor land management.

They often occur in mountainous regions where loose material can easily slide downhill. The force of rocks, soil and other debris moving quickly down a slope can devastate everything in its path. Because landslides and debris flows occur quickly and with little notice, it is essential to be prepared.

Before a landslide/debris flow

  • Review your family preparedness plan.
  • Establish a family communications plan.
  • Assemble a disaster supply kit.
  • Have a family evacuation plan in place.
  • Perform a ground assessment of your property, and consult a professional for advice on appropriate preventive measures.
  • Learn the history of landslides and debris flows in your area. Never build a home where landslides and debris flows have occurred in the past. They are likely to occur again.
  • Minimize hazards:
    • Plant ground cover on slopes. Use erosion-preventing plants such as yucca, bamboo, vetiver grass, etc.
    • If possible, build retaining walls, channels or deflection walls around your home.
  • Be familiar with landslide and debris flow warning signs:
    • New cracks appear in plaster, tile, brick, foundations, sidewalks, etc.
    • Doors and windows stick or jam for the first time.
    • Outside walls, walkways or stairs pull away from the building.
    • Underground utility lines break.
    • Water breaks through the ground surface in new locations.
    • A faint rumbling sound is noticeable and increases in volume.
    • The ground slopes downward and may begin to shift.
    • Fences, utility poles, decks, floors, retaining walls and trees tilt or move.

During a landslide/debris flow

  • Be prepared to evacuate and do so immediately if necessary.
  • If you are inside, remain where you are and take cover under a sturdy piece of furniture.
  • If you are outside, run to the nearest high ground away from the landslide or debris flow.
  • If escape is not possible, curl into a tight ball to protect your head.
What’s the difference between a landslide and a debris flow?
Landslide: Masses of rock, earth or debris moving down a slope. Think of a landslide as a large chunk of material that slides down a surface.
Debris flow: Rivers of rock, earth and other debris saturated with water. The addition of water makes debris flows more fluid than landslides.

After a landslide/debris flow

  • Stay away from the slide area. There could be additional slides.
  • Avoid using the phone except in serious emergencies.
  • Remember that flooding may occur after a landslide or debris flow.
  • Help injured or trapped people. Do not move seriously injured people unless they are in immediate danger of death or further injury. Call for help.
  • Inspect your home:
    • Leave the house if you smell gas or chemical fumes.
    • Check for damage to walls, the foundation, the electrical system and water lines.
    • Clean up spilled medicines, bleaches or other flammable liquids immediately.
    • Notify your insurance company and Habitat affiliate if your home is damaged.
  • Report any broken utility lines or damaged roadways to authorities.
  • Replant damaged ground as soon as possible to reduce the risk of flash flooding.

Additional resources

Emergency/preparedness information

Current landslide information

Other information

Floods and flash floods

Some floods develop slowly, while others develop in just minutes. Being prepared and taking mitigation measures, such as building away from floodplains and elevating homes, can reduce the risk of damage and injuries in a flood.

Read more

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