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Los Angeles (CNN) -- Monsoon-like conditions overwhelmed southern California on Wednesday, creating flash floods that kept workers at home and businesses and streets knee deep in mud and water.
The National Weather Service issued a flash flood warning Wednesday afternoon for much of Los Angeles County and for several parts of San Bernardino and Riverside counties. The Mojave Desert also was included in that warning.
As many as 40 homes in the San Bernardino County community of Highland were damaged by mud and water after two small rivers in the foothill town overflowed, said Bill Peters, spokesman for the California Department of Forestry.
Gov. Arnold Schwarzenegger declared a state of emergency in six counties Wednesday as the rainstorms continued for a fifth day and another powerful Pacific front moved in.
Schwarzenegger warned of a forecast that calls for "extraordinary and continuing rainfall" that is likely to cause more flooding and landslides. His declaration authorizes state assistance for local authorities in Kern, Orange, Riverside, San Bernardino, San Luis Obispo and Tulare counties, all in southern California.
"We're preparing for what we expect to be a very heavy, severe rainstorm," said Mike Kaspar with Los Angeles County Public Works. "... In the worst-case scenario, we could be looking at as much as 8 inches more of rain in the southern California area."
Jun Cruz, 41, a nurse who lives in Loma Linda, California, described a typical scenario for homeowners and businessmen in many communities Wednesday: The morning newspaper was delivered at 7 a.m., and moments later a flash flood carried mud and water to driveways and doorsteps.
Neighbors were left shoveling the muck from the front of their houses, but many of them couldn't go to work because their cars were partly submerged in water, Cruz said.
"Thank God, the mud didn't through our home," said Cruz, who's also a CNN iReporter. "The hill beside us eroded with water, and it brought the water and the mud along with it."
Snapshots of the deluge showed damage to roads and homes -- as well as youths making light of flooded streets. There were downed trees in Altadena, rescuers using canoes to reach stranded motorists in downtown Laguna Beach, and teenagers in wet suits sitting in lawn chairs asking motorists and a fire truck to splash them on a flooded Ocean Beach street.
And, in almost a surreal moment dreamt up by a screenwriter, the sun briefly broke through the dark clouds late Wednesday, and the Hollywood sign and surrounding hills had a spectacular double rainbow appear over them.
There was also an element of the macabre: Raging waters eroded part of a cemetery in Whittier, California, and the collapse of soil was close to some grave markers. The stark image was captured by a local television news helicopter, but it was unclear Wednesday whether graves were washed away.
"Everyone in the area has been affected -- street closures, detours and inability to get to work. Fears are that if they go now, it will start raining again and then they will not get home," said Timothy Gillepsie, 39, a minister in the San Bernardino Valley. He's also a CNN iReporter.
Ricky Hayner of Altadena had to hire crews with chain saws to remove the remnants of two downed trees in his backyard.
"The constant barrage of rain has caused flooding on many of the highways and local streets. This was also the cause of the tree falling, the excess water loosening the roots," he said.
It wasn't a good day for "the infrastructure," as one San Diego commuter put it.
"The streets are flooded. Fences are completely knocked down. There are tree branches down. I saw a lot of that on my way to work," said Michelle Johnson, 37, a project manager in San Diego, who arrived to work 45 minutes late. "But I got here. It was really crazy."
Kristiana Kocis, a Red Cross spokeswoman, reported that six people were in a shelter in a high school in San Luis Obispo and 15 more were in a shelter in Guadalupe.
The five-day rain total has topped 10 inches in many areas, with heavier amounts in some places. Twin Peaks in San Bernardino County has received more than 21 inches, with Twin Creek getting nearly 20.
Amtrak said on Wednesday it had suspended its Pacific Surfliner service between San Diego and San Juan Capistrano because of mudslides and flooding. "No alternate transportation is available," the company said in a statement. Pacific Surfliners were operating between San Luis Obispo and San Juan Capistrano via Santa Barbara and Los Angeles, Amtrak said.
In Orange County, authorities were on the scene of a mudslide that affected homes in the Silverado Canyon area, the county's Fire Authority said on Twitter. Rescues were needed, and evacuations were under way, according to the Fire Authority.
In Los Angeles County, meanwhile, authorities ordered the evacuation of more than 230 homes in two neighborhoods out of fear of debris flows. Of the 232 homes ordered evacuated in the La Canada Flintridge and La Crescenta areas, however, only one family left, said Nicole Nishida, spokeswoman for the Los Angeles County Sheriff's Department.
In Kern County on Wednesday morning, crews braced for the next storm front and sandbagged areas prone to flooding, county fire department spokesman Sean Collins said. Several roads were impassable Wednesday due to flooding, he said.
But in southwestern Utah, a dam that authorities had feared was in imminent danger of giving way to floodwaters was found to be in stronger condition than previously believed, said Marc Mortensen, a spokesman for Washington County.
The roughly 800 residents of the towns of Virgin and Rockville were allowed to return to their homes Tuesday night, Mortensen said. Engineers will monitor the dam, located on the Virgin River, and conduct more tests on Wednesday, when high water flows are expected again, he said.
Utah Gov. Gary Herbert said Tuesday he was prepared to declare a state of emergency in the south, where floodwaters also washed out at least one bridge.
Officials were keeping an eye on a bridge in the New Harmony Heights subdivision in New Harmony, Utah, said
Brian Hyer, spokesman for the Utah Department of Public Safety. That subdivision has about 25 homes, he said.
Flash flood watches also were in effect for western Arizona through Wednesday night.
In Mohave County, Arizona, the Development Services Department Operations Center was monitoring flooding along the Beaver Dam Wash and Virgin River in the Littlefield area on Wednesday.
Mohave Emergency Management official Daryle Purcell reported at least six homes are confirmed destroyed in that area, with four or five threatened. Jail inmates are being put to work sandbagging, he said.
The county was enforcing an evacuation of the area, but not everyone was complying, officials said.
"We have reports that some people haven't evacuated," Emergency Management Coordinator Byron Steward said. "We cannot force them to leave, but it certainly is in their best interest."
"Damage estimates right now are 10 homes in the Beaver Dam Resort have been damaged with at least four homes destroyed," Development Services Director Nick Hont said. "We have reports that we may lose three or more of those damaged homes in that development."
The series of storms originating in the Pacific are known as the "Pineapple Express" because of their origin near the Hawaiian Islands. They have brought heavy snow to the higher elevations, with torrential rainfall in lower spots and high winds.
High winds have also whipped much of the state this week, particularly at high elevations. Peak wind gusts reached 152 mph in Alpine Meadows summit in northern California, the weather service reported.
CNN's Jessica Jordan, Kara Devlin, Chuck Conder, Daphne Sashin, Christina Zdanowicz and Rachel Rodriguez contributed to this report.