Southern California is facing another major storm over the Presidents Day weekend, exacerbating the risks of mudslides and flooding in already vulnerable areas saturated with water. Recent record rainfall has weakened hillsides, closed roads, and caused significant damage to homes. While the strength of the upcoming storm remains uncertain, experts are warning about the ongoing dangers in slide-prone areas in the coming weeks and months.

The National Weather Service office in Oxnard is closely monitoring the weekend forecast and has indicated the potential for "significant flooding and mudslides," including a possibility of coastal flooding and damaging waves. There is also a moderate risk of falling trees and power outages. At particular risk are areas such as Malibu, the Hollywood Hills neighborhoods, and parts of coastal south Orange County, where landslides have already endangered homes and blocked important railroad tracks. Other affected areas include Baldwin Hills and Hacienda Heights.

The most concerning period is expected to be from Sunday night through Monday, with potential risks extending into Tuesday. Given the already saturated ground from recent storms, high-intensity rainfall from this weekend's storm could lead to further landslides and swift-moving flows of mud. Rainfall rates of up to 1 inch per hour are possible.

Meteorologist Ryan Kittell of the National Weather Service's Oxnard office suggests that the storm will likely move relatively slowly, dumping rain over one to two days. However, there is a chance that it may move faster, limiting rainfall to 12 to 24 hours. There is also a small possibility of the storm remaining mostly over the ocean, resulting in less overall rain in Southern California but possibly bringing more thunderstorms and brief, heavy downpours.

In anticipation of the upcoming storm, officials in Malibu announced the nightly closure of a 6-mile stretch of Pacific Coast Highway due to erosion, high tides, and damage from the previous storm. As for the rest of Southern California, Los Angeles, Ventura, and Santa Barbara counties are expected to face major weather risks on Monday and Tuesday, while San Diego, Orange, Riverside, and San Bernardino counties are at a minor risk.

Last week's storms had a significant impact on certain neighborhoods, with Bel-Air receiving nearly 14 inches of rainfall over five days. Such levels of precipitation can pose severe threats to densely built neighborhoods situated on hillsides, which are more susceptible to landslides.

Factors contributing to the increased risk of landslides and mudflows include accumulated rainfall during the storm and other variables such as burn scars, loose earth, and improper construction. Matt Thomas, a research hydrologist with the U.S. Geological Survey's landslide hazards program, emphasized the importance of various conditions that can predispose slopes to landslides, including oversteepened slopes, poorly developed fill, and inadequate site drainage.

Residents in the Hollywood Hills are particularly concerned, as recent events have demonstrated the potential for devastation. Dave Christensen, who witnessed his neighbor's house collapse and slide down the hill during the last storm, is worried about the approaching storm worsening the situation. Despite his attempts to contact city officials to remove debris before the next storm, progress has been slow. The Los Angeles Department of Building and Safety has informed him that plans are underway to demolish and remove the neighbor's home, but the debris may still be present when the next storm hits.

As Southern California prepares for the upcoming storm, authorities continue to monitor the situation and warn residents about the heightened risks of mudslides and flooding. It is crucial for individuals in affected areas to take necessary precautions and stay informed about the latest weather updates to ensure their safety.