Winter rainstorms in Southern California cause deadly mudslides. Take a look at some of the most recent images of the devastation.
At least 21 people have died from the mudslides that swept over parts of Southern California in January — impacting the same area that was ravaged in December by the Thomas Fire, the state’s largest wildfire on record, the U.S. Forest Service announced.
Many of the mudslide demises occurred in Montecito, Santa Barbara County — an area northwest of Los Angeles that’s home to celebrities such as Ellen DeGeneres, Rob Lowe and Oprah Winfrey, among others. However, as of Jan. 23, many of the evacuation orders and warnings were lifted for parts of Montecito, according to a statement from the Santa Barbara County Sheriff’s Office.
But search endeavours are still underway, Kelly Hoover, the public datum officer for the Santa Barbara County Sheriff’s Office, told Fox News on Feb. 9. At least two people — Lydia Sutthithepa, 2, and John “Jack” Cantin, 17- remain missing, she said.
In addition to the deaths and missing persons, several homes were destroyed from the mudslides, which were triggered after torrential rains caused flash flooding in the Santa Ynez Mountains. The flooding caused mud and debris to slide down from wildfire-charred hillsides that are stripped of vegetation, eventually reaching the communities below.
In light of the recent mudslides, here’s what you need to know.
Why do mudslides occur?
Mudslides, also known as dust flowings, are a type of landslide that can occur after a natural disaster, such as a wildfire. Debris flows often contain muds, stone and other materials.
“Human modification” of land can also make certain slopes and steep regions “vulnerable to landslides during and after heavy rains, ” according to the Center for Disease Control and Prevention, which estimates that roughly 25 to 50 people succumb per year in the United States because of land and mudslides.
But mudslides can also occur without a wildfire preceding it, according to Francis Rengers, a research geologist at the United States Geological Survey( USGS ), the science bureau for the Department of Interior.
In this particular case, “you had a large amount of rain and a burn region that didn’t need much to get going in the first place, ” Rengers said.
A firefighter stands on the roof of a home submerged in dirt and stones Wednesday, Jan. 10, 2018, in Montecito, Calif. ( The Associated Press)
A few different factors contribute to rubble flowings in Southern California, David Peterson, a prof of forest ecology at the University of Washington, told Fox News.
The Thomas Fire, which burned more than 280,000 acres and chiefly affected Ventura, Montecito, Carpinteria and Santa Barbara Counties, among others, removed “all of the living and dead vegetation that protected the clay beneath, ” Peterson told. The land quickly eroded when there was no vegetation to hold it in place.
The fire was also hot enough to “cook out” the organic matter in the soil, which helps the earth to assimilate water when it rains.
“When you have five or more inches of water in a day or two, it doesn’t buffer the impact of the rain on the clay, ” he told, adding that the soil also became very hot from the wildfires. This outcomes in the so-called “hydrophobic effect, ” which causes the soil to repulse water.
Additionally, different clay texture can also affect the seriousness of mudslides, Peterson told. As for the current situation, however, Peterson added that “the upper layer of soil get so saturated[ by the rainfall] that it became like Jell-O and only flowed downhill.”