Rain, Snow Continue to Hammer Southland : Weather: Families are evacuated from an RV park in Agua Dulce. Mountain roads near Santa Clarita are closed.

Record-breaking rain pounded northern Los Angeles County on Wednesday, forcing the evacuation of 25 families from an Agua Dulce recreational vehicle park, isolating million-dollar estates cut off by floodwaters and closing mountain roads near Santa Clarita.

Crews labored through the day to shore up an eroded levee on the San Gabriel River that threatened to give way and flood an El Monte housing tract.

At the Mexican border, federal agents rescued five people from the rain-swollen Tijuana River on Tuesday night, but two more were feared dead after being swept away in the current. Hundreds of American tourists in the San Quintin area, 180 miles south of the border, were stranded by washouts on Highway 1, the only route north through Baja California. Some food supplies were running short and Mexican officials said the road probably will stay blocked until Sunday, at the earliest.

The storm, which blanketed much of the area in a thick fog that made driving hazardous, continued a rainy siege that is expected to taper off today but resume by the weekend. A total of 1.31 inches of rain fell at the Los Angeles Civic Center between midnight and 3 p.m., easily eclipsing the old record of 1.12 for the date, set in 1969.

The season’s total rose to 12.51 inches, more than twice the normal total for the date of 6.02 inches.

The Newhall area had one of the highest rain totals in the county, recording 2.51 inches during the 24 hours ending at 4 p.m. Wednesday. The only place that measured more was Mt. Wilson, which received 4.4 inches during that period.

Northridge got 2.27 inches, Woodland Hills received 2.11 and Glendale measured 1.76 inches during that period, according to Rick Dittmann, a meteorologist with WeatherData Inc., which provides weather information for The Times.

As a precaution to keep motorists from becoming trapped, police closed streets leading into the Sepulveda Basin about 10 a.m. Wednesday as runoff water accumulated behind Sepulveda Dam. The streets were reopened by 4 p.m. The Golden State Freeway over the Grapevine, which was closed by snow drifts and winds of up to 70 m.p.h. Tuesday, remained open all day Wednesday.

Morning and evening rush-hour traffic was congested and slow on Wednesday as scores of cars tangled in minor fender-benders on the slippery pavement. Homeward-bound Antelope Valley commuters crawled along at 5 m.p.h. in a steady downpour.

No injuries were reported locally but pooling rainwater collapsed a portion of the roof of a Trak Auto parts outlet in Northridge, sending a torrent several feet deep washing through the store’s aisles. The collapse occurred before the store opened when only two employees were in the building.

About mid-day, Los Angeles County sheriff’s deputies ordered the residents of Vasquez Paradise Park at 32222 Agua Dulce Canyon Road to evacuate their trailers when a reservoir there overflowed. Although most walked out through knee-deep water, four were airlifted by helicopter.

A dozen of the residents gathered at Bartolo’s, a nearby Mexican restaurant, to eat lunch, drink margaritas and worry about their homes. Picking up the $185 bill were the park’s owners, Diane and Conrad Daigle.

“We felt badly for everyone and wanted to do our best to make them comfortable,” Diane Daigle said, tears welling in her eyes. “The park is our life’s savings and everything we ever worked for and it’s all flowing down the riverbed to Newhall.”

Sheriff’s deputies summoned engineers to determine whether the earth wall of the 10-foot-deep reservoir would hold and whether two other private ponds up a nearby canyon might give way. David Diotalevi, a Los Angeles County Department of Public Works engineer, concluded after a late afternoon inspection that the 100-foot-long dam holding back the reservoir was sound.

But, he said, “because the water behind the dam is at such a high level it’s best to keep people out.”

If the dam gave way, sheriff’s officials said the water could race down the canyon all the way to the already raging Santa Clara River and threaten other recreational vehicle parks. As a precaution, deputies suggested that residents of the River’s End Camp Ground at 13130 Soledad Canyon Road in Saugus take shelter elsewhere.

“We’re telling people at this point that they may want to consider voluntarily leaving . . . so in the event there is an ordered evacuation they won’t have to leave in such haste,” said Lt. Robert Elson of the sheriff’s Santa Clarita station.

But most of the park’s occupants were holding tight. “I was up here when the dam busted before” in 1969, said manager Corneilia Kline. “They were all flooded out in the parts above me, but down here the water only came across a road.”

Farther west, 47 multimillion-dollar Sand Canyon estates were cut off by a normally dry local wash that filled with nearly four feet of rapidly moving water. Among a group standing at Sand Canyon Road and Sultus Street watching the water was Barry King, owner of a local air conditioning company who was unable to get to his five-acre ranch.

“This happens maybe three to five times a year, but it’s worth it to me to live here because of the atmosphere,” said King, 40, who was driving a Ford pickup truck. “I’ve got a Corvette and a Jaguar in the garage, but they’re useless to me up here because of the mud.”

Around dusk, King and some other residents braved the water and hitched a ride on the back of a skip-loader that Ralph Conlon drove across the wash to reach his 20-acre ranch. Conlon said he had 10 yearling horses worth between $35,000 and $50,000 each that he had to get to higher ground from a flooded corral.

Trucker Ozzie Pozo drove the cab of his semi-trailer rig across the wash to deliver groceries to a friend, Irene Garmendia. “We’ve got nothing in the house and we’ve got hungry kids,” Garmendia said. “He came to our rescue.”

Sand Canyon Road between Soledad Canyon and Placerita Canyon was one of five roads in the area closed by flooding or mudslides caused by the rain, sheriff’s officials said. Also closed were Sierra Highway in the area of Davenport Road in Agua Dulce; a stretch of Lake Hughes Road about two miles west of the community of Warm Springs; Wiley Canyon Road from Calgrove Boulevard to Wabuska Street, south of Lyons Avenue; and Placerita Canyon Road from San Fernando Road to Sierra Highway.

The heavy rains also flooded roads crossing the Santa Clara River in Acton, leaving at least two motorists stranded, county firefighters said.

Four men escaped injury when their pickup truck stuck in the river between Bootlegger Canyon and Soledad Canyon roads. The truck, however, could not be retrieved.

“You make a dam of yourself when you go across the river like that because the water piles up on one side of the truck . . . it’s always deceiving,” Fire Capt. Ron Conway said. Another car was also reported stuck in the river about a half mile south of the truck.

In Topanga, a BMW stalled in rising waters at Oakwood Trail and Topanga Canyon Boulevard and the driver had to stand on the car’s roof waiting to be rescued. Passersby helped the man to dry ground. “We haven’t had a lot of rain in the past few years and people aren’t used to bad weather so they take risks they normally wouldn’t,” said sheriff’s Lt. Arvie Sherman.

Several mountain roads in San Bernardino County were closed on and off on Wednesday by snow, flooding, mudslides and traffic accidents, including portions of Highways 138, 173 and 195. Chains were required on portions of the Angeles Crest Highway near Kratka Ridge and Highway 38 near Big Bear City.

More than a dozen Santa Fe freight trains were delayed Wednesday while crews shored up an undermined embankment that threatened to give way and cut main line tracks near Hesperia, where as many as 50 homes were flooded.

Times staff writers Tracey Kaplan, Chris Kraul and Julie Tamaki and correspondent Blaine Halley contributed to this story.

VALLEY-AREA PHOTOS: B3