Storm Pushes Rainfall to Record Levels : Weather: Flash flood watches are posted and some mudslides are reported. A snowboarder is missing after being swept away by avalanche on Mt. Baldy.

A sporadic but powerful Pacific storm boosted monthly rainfall to a record Tuesday in part of Southern California, forced authorities to call off a search for a snowboarder swept away by an avalanche on Mt. Baldy, prompted a new round of flash flood watches and triggered scattered mudslides.

In San Bernardino County, searchers planned to return to Mt. Baldy this morning in an effort to locate Mike Pilotti, 24, of Costa Mesa, who was caught in an avalanche while snowboarding in an “out-of-bounds area,” said sheriff’s spokesman Deputy Ken Owens.

A man authorities identified as Larry Beard, 32, of San Clemente was snowboarding with Pilotti in Big Butch Canyon, a restricted area on the east side of Mt. Baldy, when the avalanche struck about 10:40 a.m., Owens said.

Beard was able to hide behind a tree, but Pilotti was caught in the moving wall of snow. When Beard looked up, Owens said, “his friend had disappeared.”

After digging out of the snow, Beard hiked for two hours to summon help. He was taken to San Antonio Community Hospital in Upland, where he was treated for a knee injury and fractured ribs and released, said Sharon Kensinger, director of the hospital’s emergency department.

Kensinger said Beard returned briefly to the avalanche area with rescuers.

As the snow and rain grew heavier Tuesday, authorities ordered their search helicopter back to its base, Owens said. The fear of an additional avalanche forced search-and-rescue teams to suspend efforts until this morning, he said.

Rescue teams will “go back up in the morning in first light,” said Sheriff’s Lt. Les Breeden.

“Even avalanche experts get caught in these things when they’re in the backcountry,” a search-and-rescue volunteer said. “It’s not an exact science.

“When it snows, the wind blows the snow over the leeward side of the slope and it piles up,” the volunteer said. “You can get a lot of snow built up there in a pillow or pocket that has a lot of weight to it, and it builds up stress.”

The rains that hit the Southland on Tuesday triggered new mudslides, closed more roads and contributed to a series of minor traffic accidents throughout the day, authorities said.

Mulholland Highway was closed four miles north of Pacific Coast Highway because of a landslide early Tuesday, officials said, and a mudslide closed Encinal Canyon Road in Malibu. Traffic on Pacific Coast Highway was reduced to one lane in each direction because of flooding at Chautauqua Boulevard in Pacific Palisades.

Flooding also closed the transition road from the southbound San Diego Freeway to the westbound Century Freeway, Los Angeles County sheriff’s deputies said.

An inch of rain fell at the Los Angeles Civic Center between 5 p.m. Monday and 5 p.m. Tuesday, bringing the season total to 13.7 inches, said Bill Hoffer, a National Weather Service technician. The seasonal average through this date is 7.2 inches, he said.

“The main track of the heaviest precipitation stayed a little north of Los Angeles,” said Curtis Brack, a meteorologist with WeatherData Inc., which provides forecasts for The Times.

In Ventura County, the storm set a monthly rainfall record at the County Government Center and prompted a warning that Lake Casitas could spill over its dam sometime today.

The heaviest rainfall in Southern California was recorded on Old Man Mountain along the Ventura County-Santa Barbara County line, where 11 inches fell in the 24 hours ending at 5 p.m. Tuesday, the National Weather Service said.

With a flash flood watch extended until 9 a.m. today, the Santa Barbara County Sheriff’s Department issued a public advisory urging parents to teach their children about the hazards of playing near fast-moving creeks and rivers.

“Invariably, we have people that try to ride the rapids, and it’s very dangerous,” said Senior Deputy Chuck Buttell.

“They don’t call it a flash flood for nothing,” he said.

Despite Tuesday’s rain-related problems, authorities said Ventura County’s most saturated areas fared better than expected.

The volume of water in the Ventura River and its tributaries rose steadily before dawn Tuesday, then peaked about 7 a.m. and began to recede during a lull in the showers.

“We’re below panic levels on all of the predictions,” said Dolores Taylor, a senior engineer in the county’s Flood Control Department.

So far, Ventura County is more than 200% ahead of the normal rainfall for this time of year, with totals varying by area.

This week’s showers also shattered a 25-year-old record for monthly rainfall in Ventura. By Tuesday morning, 15.1 inches of rain had fallen at the County Government Center, compared to the 13.37 that fell during January, 1969, the previous record.

“And it ain’t over yet. We’re getting more rain tomorrow,” Taylor said Tuesday.

Times staff writer Nieson Himmel in Los Angeles and correspondent Paul Elias in Ventura contributed to this report.