Each year, thousands of landslides occur, but most of them are minor. They appear in all regions, but cause the most damage in mountainous regions along with lowlands. Landslides of important calibre do happen less frequently, approximately once every ten years.

Facts on landslides

• A landslide is a collapse of rocks or non-consolidated sediments provoked naturally or by human activities.
• A landslide can be very slow or very quick.

Minimizing the risks related to landslides

The risks related to landslides can be minimized using different methods :

Avoidance

By using comments by experts and a methodical planning, communities can determine risky slopes and restrict or keep under surveillance dangerous zones.

Protection measures

• In already established communities, local authorities must determine whether to take civil engineering protection measures or to buy-out some properties in order to move their occupants.

Civil engineering solutions

• If living in proximity of risky slopes, there are many civil engineering solutions to prevent landslides, in particular :
• improving drainage;
• reducing the angle of the slope;
• excavating the top of the slope;
• building a berm or protective wall to reinforce the bottom of the slope.

Containment or diversion structures

• When we can’t prevent or avoid landslides, there are available measures of physical containment or diversion structures, in particular :
• catchment dams and containment basins to retain the debris and water;
• artificial channels or chutes to redirect the debris;
• artificial nets and walls in order to prevent falling rock or earth from reaching the roads or structures.

How to protect your house against landslides

Even if landslides generally occur without notice, understanding this natural danger and following certain rules can allow you to protect your family and household.

• Be informed about your region’s geology and the possibility of landslides occurring.
• Avoid activities that could increase instability. For example, do not dig in a steep slope, do not build near the summit or at the bottom of a steep slope, do not use fill on steep slopes, do not drain pools in a steep slope and do not increase the water flow down steep slopes.
• Learn to detect possible risks in your area. Here are a few examples : a crack or bulge in a slope, unusual water flow on a slope and collapse of small rocks or sediments.
• Know who to signal those risks to (for example: local emergency team and engineers)

What do to when a landslide occurs

If you are inside

• Take refuge in the part of the building that is the furthest away from the landslide.
• Take refuge under a solid table or bench.
• Hold on firmly and don’t move until all movement has ceased.

If you are outside

• Get away quickly from the likely trajectory and stay away from embankments, trees, electric lines and poles.
• Do not approach the area where the landslide took place. In the following hours and days, the slope could be affected again.