Mudslides are rapid movements (up to 50 mph) of large masses of mud moving downhill.
The mud in mudslides is formed from loose soil and water. Factors that contribute to the triggering of mudslides include a high water table, heavy rain, and snowmelt. Mud with fine grained sediments won't need as steep of an incline as mud with coarser grained sediments. Slopes where deforestation and urbanization has occurred are at a greater risk of experiencing mudslides than slopes with vegetation.
- Learn if there has been a history of mudslides in your area
- Learn of any local evacuation/emergency procedures
- Create a family emergency plan
During Heavy Rainfall
- Listen for any warnings on the radio
- Listen for rumbling sounds which may suggest an approaching mudslide
- If you spot a trickle of mud in a creek/stream, get away from it as for it can be a precursor of a larger flow of mud
- If you see an approaching mudslide, get out of its path and to high ground or take cover under heavy furniture (e.g., a table, a desk, etc)
- Check for trapped/injured people, but don't enter the path of the mudslide as for more mudslides may occur
- Listen for instructions on TV/radio
- Report any downed/broken utility lines/cables
Debris Flows are similar to mudslides except in the fact that debris flows have a higher density (about 2 tonnes per cubic meter, or 2 grams per cubic centimeter). Some debris flows have speeds exceeding 20 miles per hour. Debris flows can be extremely devastating, some causing tens of thousands of fatalities.