After just experiencing several days of intense storms caused by atmospheric rivers, Southern California was hit by Santa Ana winds on Monday, December 29th. The National Weather Service (NWS) has predicted that around the New Year, Southern California will face another round of rainfall, with the combination of strong winds and rain potentially exacerbating the risk of landslides and mudflows in mountainous and valley areas.
According to the National Weather Service’s warning issued on Sunday, Los Angeles County and Ventura County were expected to experience extremely strong winds from Sunday to Monday. Most areas were under high wind warnings, with wind speeds in some mountain regions reaching 55-85 miles per hour, and the gusty winds were expected to persist until Tuesday.
Similar warnings were also issued for mountain and valley areas in San Bernardino County, Riverside County, and the Santa Ana Mountains.
The Weather Service cautioned that the strong winds could topple trees and power lines, leading to widespread power outages; unsecured items could be blown around by the wind; and transportation networks could be affected: strong crosswinds pose a particular danger to high-profile vehicles, and maritime navigation could also be at risk.
Santa Ana winds, also known as Foehn winds, are hot dry winds that occur in Southern California and northern South America during the autumn and early winter. These winds are often strong and are considered one of the reasons behind the rapid and intense spread of wildfires in California. However, this current onslaught of strong winds may present a different kind of threat.
In the week leading up to Christmas, California experienced consecutive days of heavy rain and storms, which led to flooding, mudslides, and mudflows in many areas. Various agencies have launched numerous water and even aerial rescue operations. The Weather Service pointed out that due to the wet soil from the previous week’s heavy rains, the risk of tree falls has significantly increased with the arrival of the Santa Ana winds this time.
Additionally, starting from Wednesday (31st), Southern California might face another round of rainfall. The Weather Service predicts that from Wednesday to Saturday, there could be light to moderate rain. Coastal and valley areas are expected to receive 1-3 inches of rainfall, while southwest-facing foothills and mountain regions could see 3-5 inches of rain, potentially leading to landslides and mudflows on mountain and valley roads.