A fierce storm that swept through the state and left at least three people dead pounded Southern California, sending mud and floodwater gushing near fire-scarred mountain hamlets, downing trees, caving in roofs and drenching streets and highways.

By Wednesday night, the storm had dumped more than two inches of rain in downtown Los Angeles and more than 10 inches on Mount Baldy (search).

The downpour eventually moved southwest into Imperial County and Baja California. Another storm was expected early next week.

Pooling rain partially collapsed the roofs of at least a half-dozen businesses and an apartment building in Los Angeles and Orange counties. No injuries were reported.

Despite the problems, skiers and firefighters may have found reason to cheer the storm.

It signaled the beginning of ski season in the Sierra Nevada, where the giant Mammoth Mountain resort was opening Thursday.

And the moisture was expected to greatly reduce the danger of Southern California's fire season. Three national forests downgraded fire danger from "extreme" to "moderate" while reopening land that had been closed to prevent visitors from sparking blazes.

Seizing on a break in the weather, rescuers managed to locate 10 of the hikers missing in a blizzard that also killed two climbers stranded on the face of El Capitan in Yosemite National Park.

Four of the missing hikers were rescued. Also found — but not yet rescued — were four members of a Santa Cruz County winemaking family who had been missing since Sunday from a 9,400-foot-elevation lake east of Fresno in the Sierra National Forest.

Two Japanese climbers were found dead in Yosemite National Park (search) after heavy snow and winds prevented a helicopter search Tuesday. The climbers, described as ill-equipped, were dangling about two-thirds of the way up a 3,200-foot face of El Capitan (search).

In Southern California, two pipelines that send gasoline and jet fuel to Phoenix and Las Vegas remained shut Thursday while workers repaired damage caused by the severe weather. One pipeline was underwater, and the other was shut down when a freight train derailed on top of it after nearby railroad tracks were washed out.

Officials were worried about possible gas shortages in those markets if the pipelines had to remain offline for an extended time. A spokesman for Kinder Morgan, which operates the pipelines, said it was unclear when they could be reactivated.

The first heavy rain of autumn hit particularly hard in the foothill and mountain areas.

In Angeles National Forest (search), the body of a 19-year-old security guard was discovered Wednesday about a half-mile from the site where he was swept away after his truck slipped into a wash while patrolling the Wildlife Waystation.

The Los Angeles County coroner's office identified the guard as Alex Levin of Tehachapi. An autopsy was underway Thursday, said spokesman Scott Campbell, adding that Levin may have died of drowning with multiple traumatic injuries.

In Agua Dulce, Colette Smith said a man with a tree branch saved her from being swept away when a small hotel was flooded.

"He threw out a ... stick and I just grabbed on" and managed to get out of the surging, muddy flow, Colette Smith told KABC-TV. "I didn't have time to think about what had just happened."

In the San Bernardino Mountains, where hundreds of thousands of acres of forest land burned last fall, heavy rain sent floodwater and tons of mud gushing across roadways. Rushing water also made roads impassable near Lytle Creek, not far from the spot where a flash flood killed 14 people at a mountain camp last Christmas.

Interstate 15, the main highway between Los Angeles and Las Vegas, was shut down for hours when at least 40 vehicles, including two big-rigs, collided in dense afternoon fog in Cajon Pass (search). No major injuries were reported.

In the same area, flash flooding left a field of boulders over a road, stranding several dozen homeowners.

Students at an elementary school in Yorba Linda in eastern Orange County will temporarily take classes at a nearby high school because their school's hallways and classrooms were covered in muddy water that didn't go down a clogged storm drain.

Some people had to be rescued after their cars and trucks were submerged to the door handles along a flooded road in Rancho Cucamonga. Soggy ground collapsed at a mobile home park, forcing the evacuation of more than 30 families

In San Diego, more than a dozen streets were closed due to flooding, and the water covered parked vehicles in some areas, police said.