Reuters

A deadly Pacific storm, the second "Pineapple Express" weather system to sweep the West Coast in less than a week, dumped torrential rain over Southern California on Monday, triggering street flooding and mudslides throughout the region.

Extreme-weather advisories for floods, high wind and winter storm conditions were posted on Monday across parts of California and southwestern Arizona where some 35 million people live, and authorities urged residents to limit their driving.

The National Weather Service documented staggering rainfall amounts from the storm, which lashed Northern California on Sunday with hurricane-force gusts of wind, along with heavy precipitation that intensified as the system moved south on Sunday night and Monday.

The National Weather Service (NWS) said more than 10 inches of rain had fallen since Sunday across the Los Angeles area, the nation`s second-largest city, with much more expected before the downpour was due to taper off later in the week.

Nearly a foot of rain was measured over a 24-hour period on the campus of the University of California at Los Angeles (UCLA).

"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 LA, told an evening news conference. "Going back to the 1870s, this is one of the top three."

US President Joe Biden spoke to California Governor Gavin Newsom and Los Angeles Mayor Karen Bass and pledged to provide federal aid to areas hard hit by a Pacific storm pummelling the state, the White House 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 by Monday morning.

In one such incident, a fire department helicopter team rescued a man who had jumped into the churning waters of the Pacoima Wash, a concrete flood channel, in a desperate attempt to save his dog, department officials said.

The man was ultimately hoisted to safety, as seen in video footage shot by a firefighter and posted to social medial, while his pet managed to dog-paddle to the edge and also survived.