Earth Watch : Rain Increases Concerns Over Studio City, Agoura Hills Houses

The leading edge of a brisk arctic storm moved inland from the Pacific Ocean on Thursday, bringing Southern California its first substantial rain in nearly a month and increasing concerns over earth movements threatening houses in Studio City and Agoura Hills.

Heavy rain began pounding Los Angeles shortly after sundown Thursday, causing Los Angeles police to close streets leading through parkland in the Sepulveda Basin in Encino.

The National Weather Service warned there could be urban flooding during the night and into this morning. Forecasters said as much as 2 inches of rain could fall in some parts of the Los Angeles Basin by this afternoon.

Scattered showers were reported over a broad area, with Santa Barbara recording more than 3 inches of rain by mid-afternoon Thursday. Up to 2 inches will have fallen in the Los Angeles area by this afternoon, forecasters said.

The rains will tail off tonight and Saturday, but a new, less powerful storm could arrive Saturday evening, with the weather becoming fair Sunday and Monday, said Steve Burback, a meteorologist with WeatherData Inc., which provides forecasts for The Times.

“It may be wet into early April,” Burback said. “I don’t see an end in sight.”

As the storm approached Los Angeles, more than 160 county workers spent Thursday sandbagging behind two houses in Agoura Hills.

There was a small landslide on a hillside behind one house in the 27300 block of Provident Road this week, and sandbagging continued into the night Thursday in an effort to prevent more damage, Los Angeles County Fire Inspector Robert Lockett said.

Although no new movement had been reported by Thursday night, water had entered some of the structures and work crews were expected to continue to sandbag into the night as a precaution against more sliding behind and flooding in front of the house.

Meanwhile, Los Angeles building and safety engineers continued to monitor a Studio City neighborhood where a sliding hill had seriously damaged one house and threatened others. Residents from about half a dozen homes in the area were temporarily evacuated Tuesday when a 300-foot stretch of hillside began moving behind three houses.

The return of the rains results from fluctuations of the polar jet stream, a high-altitude current of air that flows from west to east across North America, forecasters said.

The stream swung south across the main body of the United States in January and February, pulling storms from the Pacific Ocean across Southern California, said Dean Jones, another WeatherData forecaster.

The jet stream swung farther north around March 1, he said, and high pressure over the West Coast blocked the storms from entering Southern California.

Jones said the region is in an uncertain transition period during which the path of the jet stream probably will be swinging back and forth.

The stream is pretty far south now, and that is why Southern California will be getting rain.

The snow level is down to 5,000 feet, with 8 inches or more expected in some parts of the San Gabriel and San Bernardino mountains and winds will gust from 25 to 35 m.p.h. in the mountains and from 15 to 25 m.p.h. along the coast, Burback said.

At the Los Angeles Civic Center, .11 of an inch of rain had fallen by 3 p.m. Thursday, raising the total for the season to 23.95 inches. The normal season’s total for the date is 13.13 inches.

Staff writer Julie Tamaki contributed to this story.