A deadly Pacific storm, the second 'Pineapple Express' weather system to pummel the West Coast in less than a week, dumped torrential rain over Southern California on Monday, leading to streets being flooded and triggering more than 120 mudslides. The brutal weather system has already claimed the lives of at least three people. At least two of those were killed by wind-toppled trees - an 82-year-old man in the former gold rush town of Yuba City and a 45-year-old man at Boulder Creek in the coastal Santa Cruz Mountains.

As emergency services rush to save lives across the Golden State, one of the most dramatic of rescues saw an LA Fire Department helicopter hovering above a raging L A River to save a man who had ventured into the torrent to rescue his dog. The man was hoisted to safety and flown to a hospital. The dog was also able to swim to safety.

The normally calm waterway roared back to life as the rains fell and was on the verge of bursting its banks. More than a foot of rain fell in just 24 hours with the storm not expected to taper off until later in the week.

Even Hollywood A-listers were not spared with houses in the Hollywood Hills and Beverly Hills at risk of both flooding and mudslides as mud and boulders were sent careening down hillsides dotted with multimillion-dollar homes.

On Monday afternoon, LA Mayor Karen Bass issued a state of emergency declaration because of the flooding. President Joe Biden spoke to California Governor Gavin Newsom and LA Mayor Bass, pledging to provide federal aid to areas hit hard.

The deluge raised concerns for the region's large population of homeless people, many of whom set up encampments along the river and on small dirt outcroppings and brush-covered islands. First responders patrolled the LA River and swift-water rescue teams were poised to deploy.

The river flows through 14 cities from the San Fernando Valley through downtown Los Angeles and south to Long Beach, where it empties into the Pacific Ocean. For decades, the 51-mile waterway largely existed as a no-man's land, a fenced-off, garbage-strewn scar running through the city.

It served as an occasional set for Hollywood movies - 'Grease' and 'Terminator 2: Judgment Day' among them - and is a frequent canvas for graffiti artists. Los Angeles officials reported 120 mudslides and debris flows throughout the city on at least 25 structures damaged by heavy rainfall or mudslides as of Monday evening.

The luxury homes and various upscale communities built on the slopes of the Hollywood Hills, Beverly Hills and Topanga Canyon were among the hardest hit by from landslides. Beverly Hills resident Jeb Johenning, standing in a neighborhood where cars stood half buried in muck and debris, said he noticed three fissures had opened on a hillside near his home, releasing 'an avalanche of mud' down the slope. 'I was driving up here last night, right after the Grammys, and coincidentally, my neighbor, who was in this SUV behind us, was being dropped off at his house, and the driver's coming down the hill, and the mud is chasing the driver,' Johenning recalled.

So far, portions of Los Angeles County received more than 10 inches of rain since Sunday Some areas, such as Bel Air and Sepulveda Canyon, saw nearly a foot of rainfall Among those who lost their lives are two Californians hit by falling trees including a 41-year-old man from Sacramento County and a 45-year-old resident from Santa Cruz County The storm system brought heavy snowfall to California's mountains, contributing to snowpack accumulation in the Sierra Nevada.

In response to flooding, 100 unhoused individuals were evacuated from a tiny home complex in Los Angeles on Monday Los Angeles Mayor Karen Bass stated during a news conference that evacuations for the homeless population are ongoing.

Still, the overall extent of property damage in the region appeared less severe than might have been expected given record amounts of precipitation. Rainfall rates were lessening as the storm wore on, and last summer's Southern California wildfire season was mild compared with some previous years, leaving more hillsides and canyon walls able to withstand a heavy soaking without collapse.

Flooding posed a considerable hazard. Rescue teams pulled dozens of people to safety statewide, mostly motorists trapped in their cars by rising waters when they tried to drive through flooded roadways, Evacuation orders were in effect for several neighborhoods at particularly high-risk of flash floods and mudslides Harry and Meghan, George Clooney, Lady Gaga and Halle Berry were among high profile celebrities whose mansions were under threat by the severe storms.

Early on Monday LA firefighters rescued 16 people from nine properties in Studio City - the same neighborhood where George Clooney lives in his $2.2 millions luxury pad. Harry and Meghan's $14.65million Montecito mansion in Santa Barbara Country, north of LA, was also at risk of flooding but the warnings subsided by Monday afternoon. The estranged prince has fled the floodwaters to be in London following the news that his father has been diagnosed with cancer.

Star-studded Malibu was also being slammed by the torrential rain with the city under a coastal flood warning. Extreme-weather advisories for floods, high wind and winter storm conditions were posted across parts of California and southwestern Arizona where some 35 million people live with authorities urging residents to limit their driving.

The National Weather Service recorded staggering rainfall amounts from the storm, which lashed Northern California with hurricane-force gusts of wind, along with heavy precipitation that intensified as the system moved south during Monday. Nearly a foot of rain was measured over a 24-hour period at the University of California-Los Angeles. 'We're talking about one of the wettest storm systems to impact the greater Los Angeles area' since records began, Ariel Cohen, chief NWS meteorologist in L.A., told an evening news conference. 'Going back to the 1870s, this is one of the top three.' 'We need every Angeleno to use common sense and stay safe and stay out of the way,' Mayor Bass said.

Bass said she had visited some of the areas hit by mudslides and debris. 'I spent time with our fire chief going around town, looking at some of the what is really devastation for many home owners and residents,' Bass said The Los Angeles Police Department reported scores of traffic collisions with injuries since the storm began, many more than usual, while city Fire Chief Kristin Crowley said her crews had responded to at least 130 flooding incidents.

The intense rainfall, with heavy snow in high-elevation mountain areas, was carried to California by a storm system meteorologists call an atmospheric river, a vast airborne current of dense moisture funneled inland from the Pacific. Winds gusting to 75 miles per hour on Sunday downed trees and utility lines across the San Francisco Bay Area and California's Central Coast, knocking out power to roughly 875,000 homes at the storm's peak in that region. About 215,000 people statewide were without power late on Monday night.

The greatest flash-flooding threat on Monday centered on Southern California, the NWS said, as the system slowly pivoted and pushed farther into the interior of California, but forecasters said 'catastrophic' impacts were unlikely. 'There's widespread, significant flooding, and locally serious and severe flooding, but nothing that is completely off-the-walls insane,' UCLA meteorologist and climate scientist Daniel Swain.

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