Stormy Pattern Persists in Southern California as Flood Advisories, Debris Flows, and New Rounds of Rain Shape the Week

A Region Still Unsettled by Repeated Storms

The atmosphere above Southern California remained charged as another pulse of heavy rain swept across Los Angeles County on Monday. Streets in Los Angeles, CA turned slick and dim under fast-moving clouds, while distant thunder pushed through the valleys. Residents described a day that shifted from steady rainfall to sudden bursts of wind and rumbling skies. One man in the San Fernando Valley said, “The whole street went dark for a moment, then the trees started bending. I heard branches snap somewhere behind the houses."

The core of the storm peaked between 3 p.m. and 7 p.m., leaving toppled trees, blocked roadways and a trail of debris from the coast inland. A flood advisory stretched across northern and western parts of the county until midnight, reaching Malibu, the San Gabriel Valley, the Santa Clarita Valley, and eastern Ventura County.

By the evening hours the rain began to weaken, but the threat did not fully disappear. Meteorologist Lisa Phillips noted that conditions remained ripe for roadway flooding, mudslides and rockslides on canyon routes. “We are looking at similar hazards as before, with potential debris flows out of burn scars," she explained.

Burn Scars Under Pressure as Rainfall Intensifies

Forecasters warned repeatedly about the Palisades, Eaton and Bridge burn scars. Those slopes carried a 40 to 50 percent chance of debris flow, a dangerous type of downslope movement in which rapid rain collects mud, rocks and broken vegetation into a rushing mass. These flows can drift across driveways or surge fast enough to push vehicles at speeds nearing 35 miles per hour.

A woman in Monte Nido, CA described the moment rocks began tumbling onto a nearby road. “You could hear the hillside cracking. It sounded hollow, then the stones just started coming down."

The numbers told the story of how forceful the system had been. Warm Springs Camp, perched in the mountains above the Santa Clarita Valley, recorded 2.5 inches of rain over an 18-hour span. Pockets of the Santa Monica Mountains collected a little over 1.25 inches.

Trees Down, Roads Blocked, Travel Disrupted

The storm created a chain of hazards throughout the region. A large rock fell on the Grapevine stretch of the 5 Freeway. Additional rock falls were reported in the unincorporated community of Monte Nido and along Highway 150 in Ventura County. In Topanga and Mira Monte, entire roadways were blocked by fallen trees.

In Thousand Oaks, CA a tree crashed into an apartment building. More than a dozen residents had to leave their homes. One tenant described it plainly: “The impact felt like something huge hit the roof, then the ceiling shook. We ran outside not knowing what else might fall."

Further north, flooding and high water disrupted Santa Barbara and San Luis Obispo counties. Highway 1 closed near Santa Maria due to water surrounding the Rancho Maria Golf Course. A debris flow covered most of Highway 46 between Paso Robles and Cambria. In Camarillo, the Conejo Creek swelled until farm fields near the 101 Freeway were coated in standing water.

A brief and weak tornado remained a possibility somewhere across the Los Angeles Basin during the evening hours, although no confirmed touchdown was reported.

Transition Toward a Quieter Tuesday, but New Instability Lingers

As the main band of the storm moved southeast toward Orange County, forecasters expected scattered showers to continue into Tuesday. There was also a 10 to 20 percent chance of thunderstorms moving through with the trailing edge of the front.

Across Los Angeles and Orange counties, the day would carry a 30 percent chance of showers, with a high near 59 degrees and a low near 47. In the valleys and the Inland Empire, the chance rose to 40 percent with a high of 60 and a low near 44, and the possibility of thunder persisted.

Along the beaches, the atmosphere stayed unsettled. A slight chance of thunderstorms accompanied a forecast high of 57 and a low near 49.

Cold in the Mountains, Snow Possible Again

Mountain communities faced the coldest air of the region, with Tuesday highs around 39 degrees and nighttime lows near 17. Rain was expected to mix with snow near the 5,000-foot level, leaving about half an inch of accumulation. Light snow flurries could return from Thursday into the start of the weekend as temperatures continued to dip.

A chance for snow above 6,000 feet remained overnight Monday as the storm slowly transitioned out of the area.

Desert Zones Holding Onto Light Rain Chances

The deserts kept a slight chance of rain Tuesday with temperatures reaching 54 degrees in the afternoon and falling toward 40 at night. Another period of rain was possible on Thursday and Friday when the next system approached.

An observer near Lancaster, CA described watching the clouds thicken over the open landscape. “The sky turned this strange gray-brown before the rain arrived. You could see the line of showers coming across the flats."

A Short Dry Window Before the Next Storm

Wednesday promised the only significant pause across the region. Sunshine and dry conditions would return briefly before another Pacific system pushed ashore on Thursday.

That next storm was expected to arrive by Thursday afternoon and deliver an additional quarter to three-quarters of an inch of rain across parts of Southern California. The beaches, valleys, and inland regions would again see renewed shower chances through Friday, while mountain areas could pick up another round of snow.

Residents across the region were already watching the ground, the hillsides and the storm tracks closely. The pattern had become familiar. One homeowner in Simi Valley summed it up as she cleared grit from her porch: “It is quieter now, but you can still feel that more weather is coming."