Landslides And Rockslides – The Warning Signs

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Know the Warning Signs of a Landslide in California

Bay Area Underpinning is here to help fix all sorts of foundation issues in your home. Whether you see cracks, sloping floors, sinking or shifting foundations, or bowing foundation walls, we can help. Often, these structural and foundation problems are caused by changing moisture conditions in the soil. However, another event that may result in structural problems is a landslide.

Landslides, mudslides, and rockslides are not uncommon in California. Areas on the coast, such as the San Francisco Bay Area, are particularly susceptible. View the California Department of Conservation‘s landslide inventory map here to see if your home is in a landslide-susceptible area.

Because landslides are common in California, it is important to be aware of the warning symptoms that a landslide is happening or may soon happen. Some of these common signs include:

  • New springs or saturated ground in a place that is normally dry
  • Soil pulling away from foundations
  • New cracks in the ground or in concrete slabs
  • Rapidly increasing creek levels and increased soil content in creeks
  • Rapidly decreasing creek levels despite rainfall
  • Leaning telephone poles, trees, fences, etc.
  • Sinking or bulging roadbeds or areas of ground
  • Unusual sounds (cracking trees, boulders hitting, etc.)
  • Sticking doors or windows or gaps near door frames
  • Broken water lines or other underground utilities
  • Exterior walls, walks, or stairs pulling away from buildings

These are some of the signs that may occur before a landslide or mudslide. While some landslides happen more gradually, others occur quickly. If you notice ANY of the above signs, consult an expert and take action right away.

Why Landslides Occur in California

Landslides are merely massive movements of earth sliding down a cliff, mountain, or slope. Mudslides, also called debris flows or mudflows, are a type of landslide that involves fast-moving debris, or saturated earth (mud) flowing in a channel. Rockslides are avalanches of rocks falling down a mountain, slope, or cliff. Certain areas are more prone to landslides, but landslides are usually triggered by a specific event, often something weather-related. Recent weather conditions in California may have increased the likelihood of landslides and rockfalls. Some common natural incidents that cause landslides include heavy rains, rapid snowmelt, wet conditions, earthquakes, and erosion. All of these conditions alter the soil conditions and increase the likelihood that a landslide will occur.

You may be more prone to experience a landslide depending on where your home sits. Homes are more likely to experience damage due to a landslide if they are located in one of the following places:

  • Near an old landslide or mudslide,
  • At the bottom or top of a slope
  • In or at the base of a drainage hollow, or
  • On a developed hillside that uses leach field septic systems
  • At the bottom or top of a fill slope
  • At the bottom or top of a steep cut slope
  • Near a channel branching off of a stream or river
  • In an area where surface runoff is directed
  • In an area that recently been destroyed/damaged by wildfire

If any of these describe the area that your home is located, pay attention to your surroundings and be able to recognize landslide warning signs.

What to Do if a Landslide Occurs Near Your Home

While there is no sure way to fully prevent or combat a landslide, there are steps that you can take to stay safe. So what should you do if you fear a landslide or if a landslide has occurred?

  1. If you live in an area prone to landslides, be prepared. This means making up an emergency kit and establishing a plan with your family. You can also prepare by getting the land around your home assessed and adding protective measures such as retaining walls and drain channels. Be sure to consult a specialist and talk to your insurance agency as well.
  2. Always remain vigilant. Landslide injury and death often occur when people are asleep. Turn on your radio during major storms and if there has been unusual weather or tremors recently, listen for sounds that are out of the ordinary. If signs of a landslide are prevalent, evacuate immediately or take shelter as best you can.
  3. Once a landslide or rockslide has occurred, stay away from the area until it has been looked at by a professional. Look for flooding, broken utility lines, and other hazards to report. Examine your foundation and home for damage. Talk to a geotechnical engineer about preventative measures and have your home repaired by a professional as soon as possible.


The most important thing to remember during or before a landslide is to stay safe. If you find that your home and foundation have suffered damage from a foundation, call us right away. We offer various underpinning and slab lifting techniques to stabilize your home after a landslide. Call Bay Area Underpinning today to learn more.

Steve Egloff

Steve Egloff

Steve is the CEO at Bay Area Underpinning, a foundation repair contractor serving the San Fransisco Bay Area, California. Bay Area Underpinning was founded in 2005 with the goal of providing a cost-effective, engineered solution to foundation settlement problems with an emphasis on educating customers to make them feel comfortable with the various methods of foundation repair.

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