Storm Fouls Up Rush-Hour : Weather: Rain causes hundreds of crashes but raises Santa Ana rainfall to normal level for season and cheers ski operators.

Southern Californians slipped and skidded to work Thursday morning as the season’s first major rainstorm made freeway driving treacherous.

The California Highway Patrol reported 70 rain-related accidents in Orange County alone and about 300 throughout the Southland, delaying commuters by as much as 90 minutes.

“Today was a bad one,” CHP Officer Ron Johnson said on Thursday. “This morning it was stopped everywhere, all the freeways. We have a sensor board that shows the speeds on the freeways, and today it was down to 20 miles per hour on most freeways.”

A small mudslide on the Chapman Avenue off-ramp of the northbound Santa Ana Freeway in Orange temporarily closed the off-ramp and all westbound lanes of Chapman Avenue Thursday morning, according to Orange police and a Caltrans spokesman.

In Laguna Beach, the storm prompted the reopening of the city’s storm operations center to help monitor the possibility of mudslides or other storm-related damage, a Fire Department spokesman said. No damage was reported in south Orange County, The rain also caused a delay for Dana Point work crews repairing the 1993 landslide on La Ventana above Pacific Coast Highway, which was scheduled to be stabilized in January, said Morton August, Dana Point director of public works, who is in charge of work on the bluff.

“We have erosion controls in place,” August said. “There’s no danger for further property damage, and we’re about 50% to 60% complete. We’ve stabilized two-thirds of the hillside and compacted the landslide area.”

For some, the storm clouds had a silver lining. At Snow Summit ski resort in Big Bear, where raindrops turned to snowflakes, folks were rejoicing.

“We’re in the snow!” cried spokeswoman Bonnie Tregaskis as the resort prepared to open this weekend. “We’ve had a couple of flakes before, but this is the first really good storm. It’s beautiful!”

Snow fell in the San Bernardino Mountains above 6,000 feet, and six inches of powder was expected to accumulate. CHP officers were bracing for an influx of skiers taking advantage of the Veterans Day holiday today and heading to resorts, such as Snow Summit.

Snow chains were required on California Route 18, but that wasn’t enough for one driver, whose vehicle went out of control and over the side of the mountain road. But CHP Officer George Berge said no one was injured.

Closer to sea level, things were warmer but no less dangerous.

Two big-rig trucks hit freeway center dividers during rush hour Thursday morning--one on the westbound Artesia Freeway in Compton, the other on the southbound Harbor Freeway.

The storm dumped .59 inch of rain on Santa Ana and .54 inch on Anaheim, but just .04 inch on San Juan Capistrano, said Curtis Brack, a meteorologist with WeatherData Inc., which provides weather information for The Times.

Fair skies are forecast for today and through the weekend, with lows in the 30s to 50s and highs in the mid-50s and 60s in the mountains and coastal areas, respectively. The high in Downtown Los Angeles on Thursday was 62 degrees and the low was 52. A total of 0.31 of an inch of rain fell.

The rain fouled many a commute, but at the Metropolitan Water District, the agency that supplies Southern California with most of its water, it was a happy sight. California is under a drought watch, and while most of the Southland’s water is drawn from either the Colorado River or reservoirs in northern California, some comes from ground water.

“The more there is down here, it lessens the need to trade supplies with the north,” said MWD spokesman Rob Hallwachs. “We never complain about rain.”

Rain Check

Less than an inch of rain fell in Orange County Thursday, but it was enough to bring up the season total to normal for this time of year. Thursday’s rain, from midnight to 4 p.m.:

City Inches Santa Ana 0.59 Anaheim 0.54 Newport Beach 0.33 Lake Forest 0.65 Dana Point 0.26 Laguna Beach 0.30 San Juan Capistrano 0.04

YEAR-TO-DATE RAIN

Santa Ana readings, as of 4 p.m. Thursday, for rain season beginning July 1:

Period Inches Season .86 Last year .11 Normal .87

Source: WeatherData Inc.