Winter Blows Into Southland Early : Weather: Area is raked with gale force winds, snow and rain. Downed lines cause power outages.

Winter descended on Southern California two days early as snow clogged mountain highways, rain pounded the foothills and chill winds hurtled down hillside canyons to batter communities throughout the Los Angeles Basin Thursday.

The gale force winds, gusting at more than 70 m.p.h. in some areas, downed power lines, fanned brush fires, shattered windows, overturned an airplane, ripped the facing from two high-rise buildings in Century City and felled scores of trees, one of which damaged a school bus in Ojai, injuring the bus driver.

Forecasters said the cold, blustery weather isn’t expected to break until Saturday--the official first day of winter--and more stormy weather could arrive here on Sunday.

The strongest winds were reported near Fillmore, in Ventura County, where gusts of up to 73 m.p.h. snapped a power line that sparked a brush fire beside California 126. Driven by the winds, the blaze spread rapidly, forcing the closure of the highway and briefly threatening a mobile home park largely inhabited by senior citizens.

More than 300 acres of brush and grasslands were blacked before 200 firefighters from Los Angeles and Ventura counties brought the blaze under control.

Another wind-whipped fire 20 miles to the east burned briefly across about an acre of farmland beside the Los Angeles County Jail facility near Castaic.

At Santa Monica Airport, home to about 550 aircraft ranging from historic fighter planes to modern corporate jets, winds of more than 60 m.p.h. flipped over a vintage Piper Cub that slammed into a private plane parked beside it, causing extensive damage to both aircraft.

“We’ve been out there trying to tie everything down,” said Gary Danforth, owner of a flight school and repair facility on the south side of the airfield. “These are the worst winds I’ve seen here in more than 20 years.”

Scores of trees were toppled from Ventura County to San Diego County, some of them severing power lines, damaging property and blocking roads.

A massive oak tree crashed down onto a school bus on California 150 between Ojai and Santa Paula, smashing the windshield and caving in the roof. Two students aboard the bus escaped injury, but the driver, Dorothy Williams, was cut on the hands by the shattering glass.

The severed power lines caused scattered electrical outages throughout Southern California.

Officials for the Los Angeles Department of Water and Power said an estimated 25,000 customers were without power during the day.

They said the neighborhoods hardest hit were in West Los Angeles, Hollywood, Wilmington, San Pedro and the eastern end of the San Fernando Valley.

Kevin Kelley, a Southern California Edison spokesman, said 12,056 customers, mostly in Santa Monica and Beverly Hills, lost power in a rash of outages late in the day.

The power outages were more widespread in San Diego County, where more than 83,000 customers were left in the dark for varying lengths of time. About 7,000 residents were without electricity for up to four hours in the Orange County cities of Huntington Beach and Costa Mesa.

A gust described by Century City residents as a powerful “whirlwind” tore decorative sheet-metal facing from two tall office buildings at the Avenue of the Stars and Santa Monica Boulevard, blasting out a corner window on the second floor of one of the structures.

The broken glass rained down onto a deserted walkway; no one was injured.

In nearby Brentwood, a tree limb crashed through the plate glass windows of a restaurant and bakery, but the patrons escaped with no more than a scare.

The snow started falling on Interstate 5 near Gorman shortly after midnight, piling up too fast for plows to keep the roadway clear. By 4:30 a.m., the state’s principal north-south highway was closed in both directions, with more than 30 big-rig trucks stalled and jackknifed on the icy pavement of the steep Grapevine grade.

The snowfall began to let up at dawn and by 8:30 a.m., the California Highway Patrol was escorting convoys of vehicles through in both directions. But the backup created a traffic jam that lasted for several more hours.

Restaurant owners in Castaic said they had hoped the clogged traffic would lead to a business bonanza, but it didn’t really work out that way.

“They come, they load up and they gridlock,” said Ed Gallo, owner of a McDonald’s restaurant beside the freeway. “So we get them in, and after that, no one else can get in.”

Jim Scimonetti, a United Parcel Service driver, whiled away the wait by donning a Santa Claus beard and playing Christmas carols on his clarinet into the speaker of his CB radio.

“We’re having a ball out here,” Scimonetti said.

About 100 miles to the north, windblown dust reduced visibility and forced the CHP to close a stretch of Interstate 5 near Coalinga for 45 minutes. It was the area where a dust storm cut across the highway on Nov. 29, setting off a series of chain-reaction collisions that killed 17 people.

The only traffic accident attributed to Thursday’s storm occurred on California 18 near Victorville, where a tractor-trailer rig skidded on icy pavement and hit a pickup truck, according to the CHP. The driver of the pickup, William Macabe, 36, of Lake Elsinore, was later reported in stable condition at a hospital in Antelope Valley.

A thunderstorm hit the Banning Pass area east of Riverside shortly after midnight, with snow reported atop the mountains on either side of the pass. The snow and thundershower activity moved west along the front of the San Bernardino and San Gabriel mountains as dawn approached, with strong snow and rain squalls reported as far west as Mt. Wilson and Pasadena.

Stephanie Hunter, a meteorologist with WeatherData Inc., said the precipitation came from a low-pressure storm system that passed through the area overnight.

She said circulation around the storm, reinforced by air whirling around an adjacent high-pressure system, brought the unexpectedly strong winds.

Hunter said skies should be clear today, but the winds will continue gusting at up to 30 m.p.h. and overnight lows will be in the mid-40s.

The winds are expected to abate on Saturday, with high temperatures in the 70s. Hunter said that the arrival of another “fairly strong” storm system on Sunday will bring a chance of more rain in the Los Angeles Basin and more snow in the mountains.

Times staff writers Lisa Castiglione, Andrea Ford, Thuan Le, Hugo Martin, Patrick J. McDonnell and Gary Thornhill contributed to this story. Free-lance writer Caitlin Rother also contributed.