Updated

The second in a series of powerful storms roared into Southern California on Tuesday, bringing heavy rains and winds that smashed windows, submerged cars and flipped an SUV along a stretch of coastline.

Forecasters said the thunderstorm was likely part of a tornado that surged ashore with fierce, rotating winds in southern Los Angeles County beach towns and areas of Orange and San Diego counties.

Kimmara Acosta, 51, a saleswoman at Castle Tile in Costa Mesa, was sitting at her desk in a showroom when she saw palm trees outside blowing horizontally.

"The wind kind of whipped through the parking lot and the window blew in," she said, still breathless a half-hour later. "It was like an explosion. My mind said 'earthquake!' and I ducked under the desk."

The wind threw shards of glass across the room, but tile displays and a desk protected Acosta. No one was hurt.

Niki Mojica, 31, a waitress at Woody's Diner in Seal Beach said, "It was crazy because the wind was coming down. The sky turned dark gray and then a huge gust of wind just blew open our front door."

Minutes later, the sky was blue, she said.

No major damage or injuries were reported.

Radar showed the thunderstorm had rotating winds like a tornado, said Philip Gonsalves, a National Weather Service meteorologist in San Diego.

Unlike twisters in the Midwest that can run for miles on the ground, Southern California tornadoes tend to start as waterspouts and dissipate quickly when they come ashore, Gonsalves said.

The gusting winds also blew a parked Ford Explorer sport utility vehicle onto its side and knocked over trees. In Irvine, a 25-foot square section of roof collapsed at a furniture company.

There also were reports of damaged boats and 16 people being displaced from flooded buildings in the San Pedro harbor area.

The fast-moving thunderstorm moved on in minutes, leaving spotty sunshine as it headed into Riverside and San Bernardino counties.

However, it left some streets underwater in low-lying beach communities and turned other roadways into muddy swamps. Televised reports showed parked cars with water up to the hoods and kayakers paddling through a flooded suburb.

Southbound Interstate 710 flooded south of Interstate 405, trapping about a dozen vehicles in water, Long Beach fire spokesman Joshua Johnson said.

"We've got a lot of flooding on streets, up to about three feet in a couple places," Johnson said. "Some homes are definitely wet, but we don't know what kind of damage we have yet."

Orange County Fire Authority Capt. Greg McKeown said there also was flooding in Westminster, San Juan Capistrano and Placentia.

In inland San Bernardino County, two boys were rescued after getting trapped in a swollen flood-control channel.

The boys, ages 10 and 12, were spotted clinging to something in the racing, muddy waters of the channel in Montclair, and firefighters used ropes and a ladder to help them up, said Inspector Steve Zermeno of the Los Angeles County Fire Department, which aided the rescue.

"The water's moving pretty fast," he said. "They're lucky someone spotted them when they did."

Flash flood watches remained for areas of Santa Barbara, Ventura and Los Angeles counties where wildfires in 2008 and last year stripped hillsides down to bare, black earth.

Los Angeles County fire officials said they would issue mandatory evacuation orders in some flood-prone areas beginning at 5 p.m. Wednesday during the next expected storm in the region.

The chance of mudslides and flooding — a worry after every rainstorm — intensified after a downpour Monday dumped 2 to 5 inches of rain in the mountains and left catch basins choked with debris.

A strong jet stream was sending the line of storms ashore from the Pacific Ocean, with the wet weather expected to continue through Thursday.

In Northern California, rain and high winds caused numerous traffic tie-ups and road closures during the morning commute.

In San Jose, three people rescued a man from a burning car when it spun out on a rain-soaked road and hit a crosswalk sign. The rescuers used a knife to cut the man loose from his seat belt then pulled him to safety just seconds before the car burst into flames, authorities said.

The man's condition was not immediately known.

Interstate 5, a main state highway, was closed in Redding due to a downed line. Highway 70 near the border of Butte and Plumas counties remained closed after a rock slid onto the roadway Monday. The rock must be blasted apart to clear the roadway.