Landslides occur in every state in the U.S. Last year, the U.S. Geological Survey (USCG) created an interactive online map to help homeowners identify their own risk. By compiling most of the data available from state and federal sources into one place, the searchable map provides a simple way to, where the data are available, see whether your home is within a landslide-prone area. In the U.S., the state of Alaska, states across the West Coast, and the Rocky Mountain states are most landslide-prone. In addition, areas in Appalachia, the Northeast, Midwest, and Puerto Rico are also impacted by landslides more frequently than other areas in the U.S.
Each year, landslides impact communities across the country. From taking lives to causing millions in property damages, landslides pose a serious and growing risk to homeowners. For example, after the Thomas Fire impacted the area of Montecito, CA, in 2018, a debris flow damaged more than 400 homes and killed 23 residents. As more areas of the country are developed and major weather events like damaging winter storms, extreme rainfall, and hurricanes are on the rise, the risk of landslides is growing.
What is a Landslide?
The term “landslide” is used to describe a diverse amount of ground movement, including debris and mudflows, rock falls, and slope failures. When a landslide occurs, the resulting soil movement can bring trees, houses, cars, and other large items with it. Gravity is the main force that causes landslides, coupled with other factors, including:
- Land erosion
- Steep slopes
- Snowmelt or heavy rains saturating soils
- Volcanic eruptions
- Man-made structures and development
For homeowners living across the U.S., the USGS has identified these commonalities between landslide prone areas of the country. These areas:
- Have experienced landslide activity in the past
- Are situated at the base of or on top of a slope
- Are near drainage hollows or an old fill slope
- Are in developed hillsides where leach field septic systems are used
Common Landslide Warning Signs
Common landslide warning signs include:
- Oversaturation of areas that are not typically wet
- Cracks or bulges in the ground, including paved streets and sidewalks
- Soil moving away from foundations
- Moving decks and/or tilting patios and other areas exterior to the home
- Cracking home foundations
- Sticking doors and windows
- Broken water lines and other underground utilities
- Leaning fences, telephone poles, or trees
- Sunken roads
- An increase in creek water levels or sudden decrease while it is still raining
- Faint rumbling sound that increases in intensity
- Sound of trees cracking or boulders falling
What to Do During a Landslide
If your home is in a landslide-prone area, stay alert and awake after heavy rainfall and listen to emergency and weather broadcasts. If you are home, move to a higher level of the building and listen for sounds of moving debris, like cracking trees. If you are driving, remember to “turn around, don’t drown.” Never drive through a submerged roadway or cross flooded streams. Watch for collapsed pavement impacting the road.
What to Do After a Landslide
If you live in a landslide-prone area, review this checklist for information on protecting your home and family after a landslide occurs.
After an emergency occurs, stay safely away from the impacted area and be watchful for more landslide activity. In addition, landslides often cause flooding, so it’s important to ensure your home’s foundation, basement or crawl space are not impacted by water damage. Remember not to touch downed power lines or move gas or propane tanks that have been impacted by the landslide. Finally, ensure your home is structurally sound and identify any damage to its foundation or other areas with a professional inspection.
A free inspection from the country’s leading foundation repair experts can help you learn what steps you can take to secure your foundation and protect your home.