O.C. Freeways Awash in Storm : Weather: Latest deluge causes far fewer problems elsewhere, but it’s small solace for snarling commuters.

High winds and sporadically heavy rainfall from a subtropical storm buffeted Orange County on Thursday, snarling evening traffic for 16 miles on the eastbound Riverside Freeway and inconveniencing motorists on several other freeways throughout the day.

But the storm, the latest in a series to strike the Southland, caused many fewer problems in Orange County than the torrential rains that inundated the region in previous weeks.

Nevertheless, public works officials across the county said they will keep a close watch for mudslides and other problems.

Silverado Canyon was deluged with more than three inches of rain Thursday, and Santiago Peak received 2.5 inches. El Toro and Lake Forest received almost an inch of rain Thursday, while Newport Beach was sprinkled with only 0.15 of an inch. Santa Ana, like most of the county, received about half an inch of rain.

Steve Burback, a meteorologist for WeatherData Inc., which provides The Times with weather forecasts, said scattered storms and occasional periods of heavy rain would continue to pelt Orange County today and tonight, bringing about an inch of rain before decreasing on Saturday.

The thunderstorm brought gusty winds to the county ranging from 21 m.p.h. to 29 m.p.h., said Lance Bucklew, a meteorologist with WeatherData.

Burback said the current storm is expected to hang around until early Sunday, pummeling the Southland with occasionally heavy rain and thundershowers. By then, he said, another storm should have arrived here from the north, bringing with it additional rain, heavy at times, Sunday afternoon and Monday.

The California Department of Transportation closed the right lane of the northbound Santa Ana Freeway for short distances at both the 4th Street and Red Hill Avenue exits late Thursday morning because of flooding, and an official said the lane would remain closed until further notice. As of Thursday afternoon, neither location had been reopened.

Commuter traffic on the Riverside Freeway slowed to a crawl between Magnolia Street in Fullerton and the Riverside County line during Thursday evening’s rush hour, as heavy rain made driving treacherous.

Urban and small-stream flood advisories were issued by the National Weather Service on Thursday for Orange, Los Angeles, Riverside, San Diego, Santa Barbara and Ventura counties. And meteorologists said the potential for damage could increase as rain and thunderstorms continue, off and on, through Monday.

At 3:31 p.m., however, the Brookhurst Street on-ramp to the westbound Riverside Freeway was closed because of flooding and had not reopened as of Thursday evening, said Caltrans spokesperson Pam Gorniak.

Flooding problems along the eastbound Garden Grove Freeway resulted in the closure of the Pearce Street over-crossing east of Harbor Blvd at 4:30 p.m. Thursday. The over-crossing will be closed until further notice, Gorniak said.

Southern California Edison reported only minor problems Thursday, most of which were due to high winds.

In Los Angeles County, the storm flooded freeways and surface-street intersections and threatened to set off mudslides and rockslides that could dismember homes on already saturated hillsides.

Los Angeles City Council President John Ferraro, who was acting as mayor in Tom Bradley’s absence, declared a state of emergency in the city, placing public works and emergency crews on special alert. The County Board of Supervisors issued a similar declaration, paving the way for financial assistance for those whose property is damaged by the storm.

Hail the size of golf balls pelted the city’s Westside as a series of thundershowers began moving through the area shortly before nightfall. Smaller hail was reported in the San Fernando and San Gabriel valleys.

Beaches were closed from Topanga Canyon to Malaga Cove for the fourth time in a month and a half when runoff overloaded sewer lines and dumped partially treated sewage into Santa Monica Bay. Officials say the beaches will remain closed until water samples show that bacteria counts are safe.

In Orange County’s hard-hit Anaheim Hills area, public works crews were keeping close watch on dozens of homes that were evacuated after a landslide during last month’s storms, but Bret Colson, a spokesman for the city of Anaheim, predicted it will be several days before they will be able to assess the effects of today’s rain.

“We may not notice any movement from the rain for a day or two,” Colson said. “We’ll have to wait and see what happens.”

Colson said that city crews had sealed up cracks in streets and sidewalks earlier this week in an effort to prevent additional water from getting into the ground and aggravating the slide.

To the north, flash-flood warnings were issued in parts of Santa Clara, San Mateo and Santa Cruz counties as wind-swept rains lashed the Santa Cruz Mountains.

Another two feet of snow was expected by tonight in the High Sierra, the principal source of water for urban Californians. While state water officials are not yet ready to proclaim an end to the state’s prolonged drought, they do confirm that the snowpack--more than 25 feet deep in some places--is well above normal for this time of year.

Contributing to this story were Times staff writers Matt Lait in Orange County and Mathis Chazanov and Edmund Newton in Los Angeles County.

Rainfall Roundup

Thursday’s storm dropped less rain than predicted, but still left more than two inches in some foothill locations. Here’s a look at the rainfall around Orange County for the eight-hour period ending at 4 p.m.

Location Inches Silverado Canyon, Station 2 3.11 Santiago Peak 2.50 Modjeska Canyon 1.38 Irvine 1.10 Brea 0.98 El Toro 0.98 San Juan Capistrano 0.98 Santa Ana 0.53 Anaheim 0.46 San Clemente 0.43 Huntington Beach 0.28 Laguna Beach 0.16 Newport Beach 0.15

YEAR-TO-DATE RAIN

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

Period Inches This Year 18.87 Average 8.44

Source: WeatherData, Orange County Environmental Management Agency