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Mudslides and Landslides Protecting from a Mudslide or Landslide: Mitigation

What You Need to Know About a Mudslide

A mudslide, also known as debris flow or, is fast-moving fluid-like landslide which flows downhill in channels. Landslides are caused by disturbances in the natural stability of a slope. They are often brought on by heavy rains or follow droughts, earthquakes, or volcanic eruptions.

According to the Centers for Disease Control (CDC) landslides and debris flows result in 25 to 50 deaths each year in the United States.

Mudslides develop when water rapidly accumulates in ground soil and mud, resulting in a surge of rock, earth, and other organic debris. They usually start on steep slopes, and may be activated by natural disasters, such as rains resulting from a hurricane.

In the United States, mudslides result in tens of deaths every year. Educate yourself on the dangers of mudslides, and develop a plan of action in the event of an occurrence. This will be important to your survival during or after a natural disaster that triggers such an event.

Hazards associated with mudslides:

  • Fast-flowing water and debris that can lead to injury
  • Broken electrical, water, gas, and sewage lines
  • Ruined railroads and highways

Areas at risk:

  • Areas where human activity has destroyed vegetation on hills and mountainsides or where wildfires have occurred
  • Areas where mudslides previously occurred
  • Steep slopes
  • Bottoms of slopes or canyons
  • Physically altered slopes for construction of buildings and roads
  • River and stream channels
  • Places where surface runoff is directed to flow

Educate yourself before significant rainfall:

  • Remember that steep slopes and areas that have been burned off are prone to mudslide activity.
  • Contact local authorities, such as a county geologist, state geological surveys or departments of natural resources and see if mudslides have happened in your area.
  • Plan out evacuation plans for your family or business.

After a Landslide or Mudslide

  • Stay away from the specific disaster site.  Additional activity may take place.
  • Check for injured or trapped people near the slide area without entering the actual path of destruction.
  • Pay close attention to radio or TV information in regards to the disaster.
  • Report any broken utility lines to the correct authorities in your community.
  • Consult with a professional engineer with soils engineering expertise for advice on reducing additional landslide problems and risks. Local authorities should be able to tell you how to contact a geotechnical expert.


Federal Emergency Management Agency

U.S. Geological Survey (USGS)

American Red Cross (ARC)

United States Geological Survey (USGS)

Center for Disease Control

Mudslides and Landslides Protecting from a Mudslide or Landslide: Mitigation
Mudslides and Landslides

Each year, thousands of mudslides and landslides occur.  However, the majority of them are minor.  They can occur in any region but cause the most damage in mountainous areas.  Larger landslides occur much less frequently; they only happen about once in every ten years.

Quick Facts on Mudslides and Landslides

  • A mudslides or landslide is a mass collapse of rocks or loose sediments that may be caused by nature or by people.

  • A mudslides or landslide can be very slow or very fast.

Minimize the Risk of Mudslides and Landslides:

  • The risk of landslides can be decreased by using several different methods:

Avoiding Potentially Hazardous Areas

  • Using input from experts and careful planning, communities can determine the areas at risk for landslides and monitor or restrict development in hazardous areas.


  • In communities that have been already established, municipal or provincial authorities should determine whether protective measures must be taken to protect the community, such as acquiring and purchasing homes in order to displace the occupants to a safer area.

Civil Engineering Solutions

  • If you are living in a potentially hazardous area, there are several civil engineering solutions that can help to prevent landslides, notably:
  1. Improving drainage.
  2. Reducing the slope’s steepness.
  3. Excavating the top of the slope.
  4. Constructing a wall or berm to reinforce the bottom of the slope.

Confinement or Diversion

  1. When it’s not possible to prevent or avoid a landslide, there are several ways of physical confining or diverting the landslide, most notably: 
    1. Containment dams or confinement basins to retain debris and water.
    2. Artificial canals to divert the debris.
    3. Nets or artificial walls to prevent loose rocks or soil from reaching roads or buildings.
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Protecting from a Mudslide and Landslide: Mitigation
Although most mudslides and landslides tend to occur without warning, effective mitigation comes from understanding this natural danger and following certain rules can help you to protect your family and home.
  • Inform yourself on the geology of your area and on the possibility of mudslides/landslides.
  • Avoid activities that can lead to instability in the area.  For example, don’t dig on a steep hill, don’t build at the top or foot of a steep slope, don’t fill in steep slopes, don’t drain pools on a steep slope, and finally, avoid anything that will increase the rate of flowing water down a steep slope.
  • Learn to detect possible risks in your region.  Here are some examples: a crack or bulge in a slope, an unusual flow of water on a steep slope, or a small collapse of rocks or sediment.
  • Know whom to call in case of an emergency.  (Who are your first responders?  Are there municipal engineers you should call?)

What to Do In Case of a Mudslide/Landslide

If You’re Indoors

  • Barricade yourself in the part of the building furthest away from the mudslide /landslide.
  • Protect yourself under a table or other solid surface.
  • Brace yourself in place and don’t move until all movement from the mudslide /landslide has ceased.

If You’re Outdoors

  • Get as far away from the landslide’s probable path and stay away from steep banks, trees, and electrical wires or poles.
  • Avoid an area that has just had a landslide.  In the hours and days that follow a landslide, the slope is susceptible to another one.
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