With critical catch basins full of muck, and more rain on the horizon, sheriff's deputies began evacuating people near where 30 houses were damaged or destroyed by a deluge of mud flowing from fire-scarred, rain-soaked mountains Saturday.   

Los Angeles County fire officials counted 41 houses damaged along the canyons streaming out of the San Gabriel Mountains, with 30 of those located on Ocean View Boulevard in Pickens Canyon. Five of those houses were described as ''very-heavily damaged'' by firefighters.   

That's where mud carried away cement K-rail and tossed cars into storm drains. Oozing debris settled at window-sill level at one home, and numerous other houses had a foot or so of mud in them.   

"Everywhere we look, we see destruction, just home after home,'' said CBS2 reporter-pilot Larry Welk. "Heavy K-rails are just tossed around.''   

Some houses in the upper reaches of Pickens Canyon had their garages doors buckled outwards toward the street, indicating that water and mud had flowed through the structures from other doors. Other homes had completely collapsed, apparently into new water chasms suddenly carved into their yards.   

Five homes in the Ocean View area were very heavily damaged, county fire inspector Matt Levesque said, and the high-water line on one home was eight feet high.   

No evacuations had been ordered overnight in the canyons, and Levesque said "this one kind of caught us by surprise.'' No weather forecasts has predicted such intense rain, he said.   

County officials fanned out at midday to evacuate about 500 homes in the same zones evacuated by prior rains, including La Canada Flintridge, La Crescenta and Acton, Levesque said.   

At least an inch of rain was expected to fall between 1 p.m. and 5 p.m., Levesque said.   

Several cars were damaged or buried by mud, he said.   

No fatalities or injuries were reported in the canyons, but three people were killed in a pair of overnight freeway wrecks related to the rain.   

A speeding pickup truck hydroplaned and flipped on the westbound Pomona (60) Freeway at Crossroads Parkway in Industry, killing two people inside it, the California Highway patrol said.   

And during heavy rain Friday night, a vehicle hydroplaned on the rain- slick Golden State (5) Freeway at Newhall, slid into the freeway median and fell 80 feet down an overpass embankment onto The Old Road. The driver was killed.   

Automated rain gauges above Pickens Canyon reported rainfall falling at the rate of one inch per hour between 6:45 and 7:45 a.m., the National Weather Service reported.   

That heavy rain followed a steady overnight rain of nearly two inches that had already filled debris basins and flood control channels protecting homes below the 250-square-mile swath of fire-denuded, steep mountains last summer.   

"It sounded like an earthquake'' at about 5:45, when boulders and a mud slurry ran down the Pickens Canyon Channel through La Crescenta and into Glendale, said resident Carolyn O'Keefe. In some places, rocks and mud crossed Foothill Boulevard, more than a mile downhill from the urban edge.

To the west, mud threatened at least one house in a steep canyon near the Hollywood Bowl. Resident Pete Morris told KNX radio that his family was gathering possessions and pets and getting out.   

"We lost a gate, and our guest house is about to come down,'' he told KNX. "I've never seen mud like this before, and we've lived here 12 years.''   

Floodwater almost a foot deep crept into businesses on Melrose Avenue, near Vine Street, said Peter Nichols, a neighborhood watch activist in Melrose Village.   

Topanga Canyon Boulevard was closed by a rock slide just north of Pacific Coast Highway, and a waterfall developed on a cliff above a propane tank company's yard in Topanga. Scattered rocks and mud fell on PCH in Malibu, where more than four inches of rain fell overnight at Big Rock Mesa.   

About 2,500 Department of Water and Power customers lost electrical service, along with about 9,200 Southern California Edison accounts. No widespread area was affected, and the outages were widely scattered.   

By midmorning, the rain had moved east. The National Weather Service warned of floods likely in foothill areas of Santa Anita, Sierra Madre, Arcadia and Monrovia -- communities below areas burned in the Santa Anita and Morris fires earlier last year -- to expect debris flows.   

"This incoming front is colder, more unstable, disturbing the air mass,'' National Weather Service meteorologist Curt Kaplan said. "This might set up a few thunderstorms and there may be a chance of water spouts, in the Huntington Beach and Long Beach areas.''     Over most of the Los Angeles basin, heavy clouds remained at midmorning, although the rain had mostly turned to light, occasional showers. Another pulse of rain was expected to fall in the afternoon, Kaplan said, adding rainfall rates could reach an inch per hour, which is considered a dangerous level in terms of mudslides.   

"Thunderstorms could bring intensities up to levels of concern,'' Kaplan said. "But that's very hit-and-miss at this point.''   

An NWS winter storm warning will be in effect for the mountains tonight. A foot or more of snow is possible at elevations of 5,000 feet or more.   

Snow levels could fall low enough by Sunday morning to affect freeway travel in and out of the Los Angeles Basin. Both main freeway passes top out around 4,000 feet.