Flash Floods in California
According to the NFIP (National Flood Insurance Program), a flood is defined as: “a general and temporary condition of partial or complete inundation of two or more acres of normally dry land area or of two or more properties…” Flash floods are floods that happen within six hours of rainfall or within six hours of another event that caused the flooding – dam or levee failure, ice jam melting or breaking, etc.
Normally, flash floods occur when there is a multiple-day succession of long and heavy rain/thunderstorms, or heavy rain caused by a tropical storm or hurricane. Early in the year, California experienced conditions perfect for causing flash floods – a series of heavy rains and thunderstorms. This is not an uncommon occurrence in the state. Now that November is well underway, the wet season is upon us. That means that Californians can expect much more rain in the next few months than in the previous.
This means basement flooding, water leakage, erosion, mold growth, and other water and flood-related damage will become a possibility.
Foundation Damage Caused by California Flash Floods
Aside from the obvious water damage that flash flooding can cause to your home and property (particularly your basement), these catastrophic events also pose a threat to the structural stability of your foundation. To understand how this happens, let us take a look at the various ways that flash floods can affect your home:
How Flash Floods Occur
Flash floods can develop in a couple of different ways. If there is a long period of consistent rain, the soil will become saturated. This can lead to flooding as the water fails to be absorbed by the soil. Flash floods can also be caused by extremely heavy rains over a short period of time, where the rain falls too fast for the ground to absorb. Other causes of flash flooding include dam and levee failure as well as melting ice jams (a less common occurrence in California). You may see a bit of water seepage into early on in the ongoing rainfall.
Pooling Water from Flash Floods
After the ground is thoroughly soaked, another rainstorm begins, or the current rainstorm continues. This added water cannot be absorbed into the ground, so it collects and pools on the surface of the ground and forms puddles near your foundation. This standing water can eat away at the concrete in your foundation and will start to soak through the porous concrete into your home, causing water seepage and weakening the foundation itself.
The Effects of Saturated Soil and Hydrostatic Pressure
If the rain continues, the water that is building in your yard and in the soil around your home might seep into your home itself. Even if not a lot of water actually gets inside, your home is still in danger. High hydrostatic pressure from the waterlogged ground surrounding your foundation causes the soil to swell and push on slab. This can cause the foundation to crack, shift, and buckle.
Because flash floods are quite unpredictable and sudden, it is important to have a plan you can rely on if disaster strikes. Bay Area Underpinning offers a variety of foundation repair solutions as well as crawl space encapsulation to repair damage caused by flash floods. Call today for underpinning with foundation piers from ECP (Earth Contact Products), carbon fiber repair, or crawlspace repair solutions to help you repair any damage caused by flash floods during this rainy season. Keep our number handy: 707-310-0602.