Highway 101 between Ventura and Santa Barbara won't open until Saturday morning as cleanup crews work round the clock to clear a sprawling mudslide north of La Conchita.

Jim Hansen, an area superintendent for the California Department of Transportation, said Wednesday's warm, dry weather was a boon to the cleanup. But a number of fixes, including the placement of a temporary concrete wall where the slide destroyed a concrete guardrail, must be in place before the roadway is safe.

Minor structural damage also was found at the Bates Road overcrossing.

"We are getting a ton of pressure to get it open," Hansen said. "We won't have this road closed one minute longer than is necessary."

The mudslide, nearly 8 feet deep in some places, smothered a swath of the freeway a quarter-mile wide after drainage ditches that run under the freeway were overwhelmed early Monday with water and debris flowing off saturated canyon walls.

"There was just too much rain, arriving too fast, that it overwhelmed the drain structures and ended up on the freeway," Hansen said.

The closure has aggravated and frustrated travelers, residents of beachside communities now isolated and businesses that depend on the major road to get employees to work, bring in materials and move goods to market. Some 70,000 vehicles traverse the highway per day, Caltrans officials said.

"The shutdown has taken a huge economic toll," said Zoe Taylor, president and CEO of Ventura Chamber of Commerce, who was in La Conchita as part of Gov. Arnold Schwarzenegger's contingent that toured the disaster area.

On Wednesday, crews using 10-ton loaders and vacuum trucks continued to remove mud and sludge from the roadway and median area. Water trucks and street sweepers ran up and down the slick, stained roadway.

"There was enough mud to probably fill a football stadium 3 feet deep," said Craig Carlson, field superintendent of Blois Construction Inc. of Oxnard, a contractor hired by the state.

Crews in excavators also worked to clear the 6-foot-wide drainage culverts choked with rock and debris that had come off the hillsides. In addition to the mud removal, the road will have to be restriped, Hansen said.

The clean-up is projected to cost $1.25 million, Caltrans spokeswoman Deborah Harris said.

There had been some talk of the southbound lanes being opened to allow some limited traffic, but Hansen ruled that out.

"We're not going to have traffic going in both directions on one side of the highway," he said. "That's not an option."

The weight and force of the slide fractured the concrete guardrail, creating a gap 60 to 100 feet wide to the ocean. Twisted or badly dented metal highway barriers slump on the side of the road.

An emergency exception allowed crews to push much of the mud and debris into the sea, Hansen said. Nonemergency situations would have required all the muck and sludge be collected and trucked to a landfill.

"To try to truck it out would have been a huge undertaking and would have meant that the highway would be closed for a longer period," Hansen said.

When dealing with a quantity of mud this large, its removal involves an effort part science, part manpower.

"You have to start at the top of the mud pile and work your way down or you are setting yourself" up for the spill to enlarge, said Michael Miles, Caltrans' deputy director of maintenance for Los Angeles and Ventura counties.

Miles used the analogy of a sand castle on the beach to describe how crews dismantled the mounds of mud.

"You see how a wave hits the bottom of the castle and undermines it until it gets to the point where it just collapses," he said. "That's why you have to work your way down."