Severe Storms/Mudslides

This page is to be used for the Severe Storms topic of the Meteorology event.

Mudslides

Mudslides are rapid movements (up to 50 mph) of large masses of mud moving downhill.

Mudslide Formation

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.

Mudslide Safety

Before

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)

After

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

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.

Resources

USGS Fact Sheet - https://pubs.usgs.gov/fs/fs-0071-00/fs-0071-00.pdf

National Hazard Center - https://hazards.colorado.edu/