According to a November Los Angeles Times article, residents and municipalities are feeling the threat of mudslides after recent California wildfires have taken a toll on life and property.

The mudslide risk is particularly concerning for those living in the burn areas of recent California wildfires known as the Getty Fire and the Palisades Fire.

The Getty fire—named for its proximity to the Getty Museum northwest of Beverly Hills in Los Angeles started on Oct. 28, 2019, and burned 745 acres, according to the San Francisco Chronicle. Containment of this blaze was reached in full on Nov. 5, but not before 10 homes were destroyed and 15 other properties seriously damaged.

The Palisades Fire burned northwest of Santa Monica on Palisades Drive in Pacific Palisades in an area of Los Angeles beset with multimillion-dollar homes. This brush fire started on Oct. 21, 2019 and was completely contained by Nov. 5 as well. Forty-two acres burned and there were 4 injuries, but no homes or structures destroyed.

Why Recent California Wildfires and Mudslides May be Linked

According to the Los Angeles Times, mudslides are part and parcel of living near the mountains in southern California, where the elevation is steep and rapidly declines in areas where water drains in a path to the nearby Pacific Ocean. The trees, brush and other vegetation which normally vibrantly grows on the foothills and mountains establish a foothold for topsoil, providing a strong anchor in the best of circumstances.

When this anchor is lost through wildfire—even temporarily—there is nothing to hold this soil and the rapidly flowing water after a rainstorm can rush to the sea carrying dirt, rocks, boulders, branches, and debris. This flow can appear like white water rapids, rushing very quickly and overwhelming the best emergency alert system.

An additional complication to this “perfect storm” of torrential rainstorms and burned-off vegetation, according to the article, is the tendency for resultant ash to clog the avenues for water to be absorbed into the soil. The ash acts as a water repellent, further encouraging run-off which can pick up a good deal of speed and volume of sediment.

There is a difference between a mudflow and a debris flow, but both are considered shallow if they are less than 15 feet deep. A mudflow carries only mud whereas a debris flow can carry massive debris like giant rocks, even felled trees. Even though these flows are referred to as shallow, they can be deadly.

One needs only to consult California history to find stories filled with loss of life and home. According to the LA Times, in 1934, a 20-foot debris flowed down a canyon after a fire and then heavy rains in Angeles National Forest. This incident was huge as 400 homes were leveled and 45 people lost their lives. As wildfires become more frequent in the state with climate change and extended periods of drought, these secondary natural disasters are of primary concern to state and regional emergency service planning.

This article is not legal advice. It is presented
for informational purposes only.