Southern California drivers slogged through a wet, slow Friday evening commute as the first of two bands of heavy rain moved through the region.

The National Weather Service said the storm could bring heavy snow to the mountains, the potential for funnel clouds along the coast, lightning and 70-mph wind gusts in mountain passes.

Officials said the region can expect strong storm activity through Saturday morning, then scattered showers followed by heavier rains Saturday night.

Numerous accidents were reported on freeways in the region, according to the California Highway Patrol. In San Pedro, the Coast Guard and Los Angeles Fire Department rescued a man whose sailboat smashed into rocks.

In the Sierra Nevada, Lake Tahoe resorts reported up to 4 feet of snow over the last 24 hours. Chains were required on many local mountain roads, where several accidents blocking roads were reported.
"A strong front will bring a four- to seven-hour period of heavy rain this afternoon into tonight," the weather service said in a statement. "Numerous showers will continue across the region through Saturday night. There will be a chance of thunderstorms at anytime from this afternoon through Saturday night."

A flash-flood watch has been issued for mountain areas that have been scorched by wildfires in recent years.

The heaviest rainfall was expected to hit Santa Barbara and Ventura counties Friday afternoon and reach the Los Angeles area in the late afternoon and last until about midnight, the weather service said.

The flash-flood watch was issued for areas that were burned by blazes such as the Station and Morris fires in the San Gabriel Mountains in 2009, the weather service said.

Those areas "will have the potential for flash flooding and debris flows," the agency said.