As witnessed by the recent weather events of scorching wildfires and damaging rain, mudslides are a very real and present danger to California residents. Heavy winter storms that produced record rain and snowfall have triggered massive amounts of debris flows. Rain saturated soil eroded in northern and southern California areas hardest hit by recent wildfires. The California mudslides have also destroyed large sections of highway, stranding residents — many of whom were already in precarious home situations.
The National Weather Service measured rainfall across California, with at least 9.4 inches of rain over 48 hours over the San Bernardino Mountains to the east of Los Angeles. When you take into account the vicious cycle of drought, wildfires, and rain/flooding, the extent of the damage we saw here in Los Angeles starts to make sense.
This particular storm was fed by an atmospheric river — moisture that extended across the Pacific Ocean almost to Hawaii. These long bands of water vapor form over oceans and are aided by storm winds that combined to lay siege to the nation’s West Coast.
For this reason and others, a professional soil analysis on your current property, or on property you wish to build on, is vital to determine the soil’s strength and viability for your project. That’s where a geotechnical engineer comes in. These engineers examine and probe the soil under house footings for its bearing capacity. They can then determine if it is wise to build a new home on that ground. If your house is being renovated or having an addition added, the geotechnical engineer can also use the soil analysis to determine if and where retaining walls, grout curtains, deflections or concrete anchors may be suitable.
The soil analysis can also pinpoint suspect areas of the property that may need to be removed and replaced with stone or an engineered landfill. The wider or thicker footings that are designed to spread out the weight of the home may need to be redesigned or modified to meet the current needs of the analysis.
In order to get the most from a geotechnical soil analysis, the investigation of the site and available plans for the site are of utmost importance.
If you’re concerned about your home or construction site’s viability during the next big rainstorm, consider getting a soil analysis performed. This can include:
Location and or map of area
Stated purpose of soil analysis
Geologic and topographic descriptions
Available soil testing
Descriptions of subsurface soil, types of rocks and groundwater
Information on test hole, lab testing and photographs
Subsurface profile information
Sample types and depths listed
Pertinent laboratory results included
Soil analysis reports contain a summary of subsurface data and profiles. Their main goal is to interpret and analyze data to provide design recommendations, revisions or solutions to existing problems or anticipated problems.
Storms like the one we recently experienced are Mother Nature’s reminders of her infinite power of destruction. Sometimes, nature is simply more powerful than we are. With that being said, having a soil analysis before you build, add on or remodel, may protect you from mudslides and storm damage more than you think.