Rain Creates Mudslides, Closes Road : Weather: Sudden downpour in South County produces wall of mud and debris that flows into Laguna Canyon Road businesses. A dry weekend is expected.

A surprise storm dumped nearly half an inch of rain over parts of Orange County, causing mudslides and road closures Thursday in fire-scarred Laguna Beach.

Mud “went through every square inch of the shop,” said Bob Chenault, manager of Stricker Automotive, which was among shops in the 2000 block of Laguna Canyon Road hardest hit by a six- to 18-inch wall of mud and debris. The road was closed, and no injuries were reported.

Chenault spent the morning shoveling mud from inside the shop and from a parking lot.

Workers at Stricker Automotive and other businesses in the complex had scrambled to try to prevent the mud and water from entering their shops. Some hastily erected a dam made of a tow truck, a flatbed truck, bricks, plywood, sandbags and anything else they could get their hands on.

“Within 10 minutes we had mud everywhere,” said Norman Wert, head mechanic at Canyon Auto Repair. “It just came down like a river. It was quick.”

A storm cell from an unstable weather system along the Southern California coast unleashed the torrent that dropped nearly half an inch of rain within an hour in Laguna Beach and .87 of an inch in Santa Ana, according to Laguna Beach Battalion Fire Chief Joe McClure and other officials who tracked the storm by computer from a city command center.

The weekend is expected to be fair and dry with some high cloudiness, said Bruce Thoren, a meteorologist for WeatherData Inc., which forecasts weather for The Times. Southern California can expect a warming trend with temperatures in the mid-60s, and possibly in the low 70s by Monday.

While only trace amounts of rain fell in Fullerton and Yorba Linda, the capricious rainstorm struck the southern portion of Orange County with moderate amounts of rainfall, including the Sand Canyon area of Irvine, which received .43 of an inch.

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“We’re faring pretty well,” said Jack Stubbs, emergency planning officer for San Clemente, which suffered a massive landslide during a rainstorm a year ago. “We’re dry and the slide area is intact.”

Similarly, Anaheim Battalion Chief Rudy Weyland reported that Anaheim Hills, which also had slides last year, came through the rain without problems.

Laguna Beach Fire Capt. Api Weinert said the storm’s quickness caught the city by surprise.

“We heard there was supposed to be rain likely by about 6:30 a.m., and we manned the command center between 7 and 7:30 a.m.,” Weinert said. “I was on the telephone with the National Weather Service, and they were telling me to expect only a 60% chance of rain when it was already raining here.”

In about an hour, nearly half an inch of rain fell on the South County city, he said. City officials said that at least half an inch of rain must fall before they will order evacuations in areas devastated by the Oct. 27 fire that swept through parts of Laguna.

The city was among victims of last fall’s firestorms, which burned off soil-stabilizing brush and grass from hills around and within the city. More than 16,680 acres of vegetation and 366 homes were lost.

A week later, a heavy downpour flooded streets and damaged homes, prompting Laguna Beach to establish a computer weather-tracking system inside a command center where workers are on call in case of the threat of rain.

Most of the silt dams, sandbagging and other diversion techniques implemented in preparation for rain kept water and mud away from homes and buildings, Weinert said.

The unstable storm also created waterspouts in the Pacific Ocean that traveled up the San Diego County coast, Thoren said.

“The upper-level system that tracked directly right over you in Orange County was not enough to develop heavy rain, but very spotty rainfall,” Thoren said. “That stuff is very hard to predict as to who’s going to get it and who’s not.”