* State of emergency declared in 5 counties
* Flights canceled, interstate closed, 25-foot waves (Updates with nearly 2,000 homes evacuated)
By Dan Whitcomb and Steve Gorman
LOS ANGELES, Jan 21 (Reuters) - The fourth and strongest winter rainstorm in a week clobbered normally sunny Southern California on Thursday, canceling flights, pounding beaches with huge waves and threatening to bring torrents of mud down on pricey hillside homes.
Californians, who have rarely seen rain during a three-year drought that left the state rationing water, found themselves deluged — forced to drive through flooded streets, bail out and sandbag their homes or in some cases evacuate.
State Attorney General Jerry Brown, acting in place of traveling Governor Arnold Schwarzenegger, declared a state of emergency in five counties.
Officials said a silver lining of the worst storms the state had seen in five years was waist-high snow dumped on mountain ranges that could ease critical water shortages, although they stopped short of calling the drought over.
The heavy rain and high winds forced Southwest Airlines (LUV.N) to suspend most of its flights from four area airports at least until Thursday evening.
Nearly 2,000 homes were evacuated in the foothills north of Los Angeles that were left blackened and barren by last year’s wildfires, as authorities feared that days of steady rain would bring down entire hillsides of mud and boulders.
But several residents on one slide-prone cul-de-sac in the community of La Canada-Flintridge, scene of last summer’s massive Station Fire, chose to stay put and help authorities channel swift-flowing, muddy water away from their homes.
“The idea is, don’t let it pile up there but keep it moving,” said 59-year-old George Witkor. “We’re trying to keep it flowing as long as we can. If it gets too deep, we are out of here”
At least two houses in La Canada-Flintridge sustained damage from mud and debris but no injuries were reported.
Flood warnings were issued for low-lying areas and beaches, some which were slammed by 25-foot (7.6 metre) waves.
Witnesses reported a tornado in Ventura County, north of Los Angeles, and authorities responding to the scene found a mile-long (1.6-km) path of destruction.
“One lady said her car hovered for a couple feet, spun around, then rammed into tree and blew out all the back and side windows,” Ventura Police Sergeant Jack Richards said.
“I’ve been here for 25 years now and never saw a tornado hit like this before. We’ve had microbursts, I’ve seen water spouts, never had anything like this,” Richards said.
Throughout the day, downed power lines knocked out power to more than 30,000 homes and businesses across California, and some schools also were closed or students kept indoors.
Interstate 5, the major artery connecting Southern California to northern parts of the state, was shut down because of snow at a mountain pass.
The desert resort city of Palm Springs has received half its average annual rainfall this week, and at least two deaths have been attributed to the storms, including a 21-year-old man crushed when a tall tree toppled on his house.
Arizona Governor Jan Brewer declared a state of emergency after storms dumped snow on the high country, triggered flash floods and caused delays at Phoenix Sky Harbor Airport. (Additional reporting by Tim Gaynor in Phoenix; Editing by Peter Cooney)