Definition of a Landslide
According to the USGS , a landslide is defined as “the downslope movement of earth materials (rock, debris, and soil) at rates that range from inches per year to tens of miles per hour.” Notably, some landslides can move at a quicker rate than a human can run. Additionally, they can occur in short bursts, or sometimes last days, weeks, or even longer.
Where do Landslides Usually Occur?
While landslides can occur in all 50 states, they tend to be more common in the Rocky Mountains, Appalachian Mountains, Pacific Coastal Ranges, and some parts of Alaska and Hawaii. Still, there are certain factors that make an area more susceptible to landslides according to the CDC, including:
- Places where landslides have occurred in the past
- Bottom of slopes or canyons
- Steep slopes
- Channels along rivers and streams
- Human activity, such as removing vegetation or modifying natural landscapes to build roads or structures
While they can occur year-round, landslides are most common between the months of November and March , when snow falls and melts, and also when spring rainfall occurs, according to Seattle’s Department of Construction and Inspections.
Outdoor damage from landslides according to the CDC, CDPH, and Yo Nature, can include:
- Flooding
- Additional landslides or mudslides
- Polluted streams
- Damaged ecosystems
- Destroyed forests
Effect #2: Broken Service Lines
A landslide may have shifted or severed electric, gas, water, and/or sewage lines, so use caution when venturing outside. Not only can these damaged lines devastate infrastructure and cause severe outages near and far, but they can prove hazardous if encountered, causing possible injury, illness, or even death.
What is the Difference Between a Landslide and Mudslide?
While the terms “landslide” and “mudslide” tend to be used interchangeably, there is a distinct difference between the two. According to California’s Department of Public Health, the difference between a landslide and mudslide is :
- Like the USGS, the California Department of Public Health notes that landslides occur “when masses of rock, earth or debris move down a slope.”
- A mudslide is defined as “a type of fast-moving landslide that tends to flow in channels.” They go on to state that mudslides develop when water rapidly forms in the ground, soaking debris, rock, and the surrounding earthen area.
For more information on mudslides, visit our articles “Signs of a Mudslide and How to Prepare” and “How to Clean Your House After a Mudslide.”
For more information, please visit our FAQ and Glossary .
Sources:
https://www.cdc.gov/disasters/landslides.html
https://www.cdph.ca.gov/Programs/EPO/Pages/BI_Natural-Disasters_Landslides-and-Mudslides.aspx
https://www.usgs.gov/programs/landslide-hazards/landslides-101
https://www.yonature.com/effects-landslides-positive-negative-examples/