During a landslide, rock, earth, or debris moves down a slope. They can be small or large, slow or rapid and there are many types with several causes – all are extremely dangerous.
- Landslides or Rock Falls – Following an intense or prolonged rainfall, rapid snow melt or changes in ground-water levels, combined with vibrations from volcanic eruptions, earthquakes or construction activity.
Mud and Debris Flows – Rock, earth, and debris become saturated with water, turning into a rapidly flowing river of mud or “slurry” known as a Lahar.
Lahars – A rapidly flowing river of mud or slurry – they can travel several kilometres from their source, growing in size as they pick up trees, boulders, cars, and other materials.
Slumping Slides – The undercutting of slopes by streams, erosion, wave action, glaciers, or construction.
Debris Torrents – The accumulation of debris, mud, and logs in a channel which forms a temporary dam – flooding occurs upstream as the water backs up behind the temporary dam. The temporary dam bursts, creating a flash flood.
Snow Avalanches – See avalanche
Avoiding A Landslide
Consider the following:
- Choose campsites away from creeks, ravines and other unstable slopes,
- Listen to a weather radio for warnings of intense rainfall,
- If you are in areas susceptible to landslides and debris flows, consider leaving,
- Stay alert and awake – many fatalities occur when campers are sleeping.
- Listen for any unusual sounds that might indicate moving debris, such as trees cracking or grinding boulders,
- Be alert for any sudden increase or decrease in water flow,
- Water turning muddy,
- If you hear a roaring sound uphill – this may be a wave of debris moving rapidly toward you!
Get out of the path of a landslide or debris flow. Run… save yourself not your belongings. If escape is not possible, curl into a tight ball, protect your head, and hope for the best.
After The Slide
Landslides can create large waves on lakes, or tsunamis in coastal regions. There may be a danger of additional slides. Flooding may occur after a landslide or debris flow.