Roads reopened, city work crews continued clean-up efforts and Los Angeles Mayor James Hahn declared a state of emergency in the aftermath of a series of storms that saturated the Los Angeles basin.

All of the canyon roads connecting the San Fernando Valley with the rest of Los Angeles were open Thursday morning, with the exception of Topanga Canyon. At times during the past week, five of the seven canyon passages were closed.

Even so, debris remained. In the Cahuenga Pass, a fallen tree blocked one of two southbound lanes, backing up commuter traffic on Cahuenga Boulevard. Both Coldwater Canyon Avenue and Laurel Canyon Boulevard reopened Wednesday afternoon from Ventura Boulevard to Mulholland Drive. But a speed limit of 15 miles per hour was in force, because city engineers found that vehicles moving faster than that could generate vibrations that could knock some more rocks and debris loose from the hillsides.

Late Wednesday, Mayor Hahn gave an initial assessment of the city’s damage and called on Gov. Arnold Schwarzenegger for assistance. Residents in the Mt. Olympus area of the city were asked to voluntarily evacuate due to ground saturation, and city work crews were putting in 12-hour shifts filling some 600 potholes that Hahn said were caused by the two-weeks of storms.

Preliminary figures put storm-related damages in the city of Los Angeles at $10 million, although that figure was expected to rise. There was no word on whether any state aid would be forthcoming.

Schwarzenegger on Wednesday toured the devastated town of La Conchita in Ventura County, where a landslide killed at least 10 people. On Thursday morning, radio station KNX-AM (1070) reported that rescue crews halted their work after geologists found the ground was beginning to move again.

While the rains are not likely to create much of an economic ripple on the area over the long term, there were numerous short-term problems that have developed. Union Pacific Corp. shut down much of its service into and out of Los Angeles due to tracks that became impassable because of the high water.

Among the lines affected by a series of mudslides was an area that goes through the Cajon Pass. Also closed was a stretch running between downtown L.A. and a switching yard near San Bernardino.

Union Pacific said it expects to repair its four damaged routes by Thursday. However, the railroad won’t be taking any additional cargo until at least next Monday, when it has removed the backlog in freight that has been piling up at the terminal yards since the tracks were closed on Sunday.

“It’s a major weather disaster,” Union Pacific spokesman John Bromley said. “We’ve never had to deal with anything like this before.”

Anthony Palazzo, Andy Fixmer, David Greenberg, Rachel Brown and Kim Holmes contributed to this story.