Storm Blamed for Pileups on Freeways : Weather: Another huge system is moving in and is expected to start pounding the Southland on Tuesday.

Another fast-moving storm pelted Southern California on Sunday, triggering several freeway pileups in what forecasters called a precursor to a huge tempest expected to pound the area beginning Tuesday.

Rain was partially blamed for a 20-car pileup on the San Bernardino Freeway that left several people injured. The early afternoon crash in West Covina was one of several multiple-car collisions on rain-slick Southland freeways, authorities said.

A five-car collision on the Harbor Freeway near Exposition Boulevard, and an eight-car crash on Interstate 5, near the East Los Angeles interchange, were blamed on the storm. No serious injuries were reported in either crash.

Los Angeles city sanitation crews said they had contained a sewage spill in Los Angeles Harbor caused by Friday’s storm, but not before nearly 12 million gallons of partially treated sewage had flowed into the harbor off San Pedro. Officials blamed the spill on a power failure.

Inner Cabrillo Beach in San Pedro remained closed Sunday as county health officials moved to determine the degree of sewage contamination in the harbor. The spill was confined primarily to the harbor, said Clarence Mansell, manager of the city’s Terminal Island sewage plant.

Late Sunday, rescue crews from the city Fire Department and the U.S. Coast Guard rushed to rain-swollen Ballona Creek in Mar Vista after receiving a report that two people were calling for help after falling into the channel.

Two helicopters, a Coast Guard vessel and several other rescue crews combed the area for nearly an hour before calling off the search, said Fire Department spokesman Bob Collis. Investigators were unable to determine if anyone had fallen into the creek, he said.

Sunday’s showers and isolated thunderstorms were expected to continue through today before the storm clears out, forecasters said. Another storm system building in the Gulf of Alaska is expected to move into Southern California Tuesday night, bringing heavy rain and winds up to 25 m.p.h. through Thursday.

“This storm is going to stick around for a while,” said Steve Burback, a meteorologist with WeatherData Inc., which provides forecasts for The Times. “There’s no sign that we’re going into a dry period for a while. The area will just have enough time to dry off before the next storm hits.”

Forecasters reported that 0.37 of an inch of rain fell at the Los Angeles Civic Center between midnight and 3 p.m. Sunday. Rainfall from the current storm is expected to reach 1 1/2 inches along the coast and up to 2 1/2 inches in the foothills and lower mountain elevations.

The snow level in the mountains dropped to 6,500 feet Sunday with up to seven inches of new snow expected from this storm in the higher elevations. Meteorologists expected the snow level to drop to 5,000 feet by midweek.

Sunday’s storm follows one on Friday that caused a variety of problems, including a 100-vehicle pileup in the Cajon Pass that was blamed on fog. One person died and 11 were critically injured in that crash.

Some fog was reported in the Cajon Pass on Sunday, but California Highway Patrol officials said driving conditions were not hazardous.

Southland Rain Watch

Rainfall figures for the 24-hour period ending at 4 p.m. Sunday. Season totals and norms are based on precipitation from July 1 to date.

REGION PRECIPITATION IN INCHES 24-Hour Storm Season Season Total Total* Total Norm L.A. BASIN Avalon/Catalina .32 2.17 12.04 10.51 Culver City .31 NA 12.10 12.38 Long Beach .29 2.52 13.32 10.43 L.A. Civic Center .33 2.05 19.04 12.85 L.A. Int’l Airport .39 1.93 13.00 10.55 Montebello NA NA 10.49 13.15 Santa Monica .12 1.95 15.14 12.16 Torrance .75 3.33 17.55 11.61 UCLA .32 NA 18.85 15.26 VALLEYS/CANYONS Beaumont .10 1.89 15.74 14.03 Monrovia .28 2.13 20.08 NA Northridge .08 2.28 18.98 NA Pasadena .28 2.78 27.00 16.72 Riverside .05 1.24 8.08 8.22 San Bernardino .10 1.83 11.26 13.21 San Gabriel .21 2.45 18.90 15.40 Santa Clarita .06 2.49 24.22 15.59 Woodland Hills .33 3.03 32.15 13.81 ORANGE COUNTY Newport Beach .20 2.06 13.47 9.32 San Juan Cap. .26 1.28 14.80 NA Santa Ana .24 1.15 12.64 10.83 SAN DIEGO COUNTY Oceanside NA NA 10.01 8.72 San Diego .03 .51 11.19 7.81 SOUTHLAND MOUNTAINS Big Bear Lake .02 1.37 14.52 19.78 Mt. Wilson .76 3.36 43.94 29.18 DESERTS Palm Springs Trace .24 6.29 4.81 Lancaster NA NA NA 6.93 SANTA BARBARA/VENTURA Santa Barbara .19 1.27 17.25 15.36 Ventura .35 1.24 19.34 12.70

NA indicates figures not available. In other cases, some totals may be incomplete because of missing station reports.

* Amount of rainfall since the last zero-precipitation day.

SOURCE: National Weather Service and WeatherData Inc.