21-Vehicle Pileup on Freeway in Irvine Blamed on Rain, Fuel Spill : Weather: Officers believe diesel combined with moisture to create slick roadway. Showers leave the area Wednesday afternoon.

Wet driving conditions and fuel leaking from a big rig apparently spurred a 21-vehicle pileup on the San Diego Freeway in Irvine, causing minor injuries and clogging traffic for two hours Wednesday morning, authorities said.

The chain-reaction crash came during a morning of sporadic downpours that flooded a library at Cal State Fullerton and contributed to scattered traffic mishaps, including the loosening of a boulder that crashed into a truck on Ortega Highway and left the driver shaken but unhurt.

Investigators said a big rig leaking diesel fuel had passed on the freeway in Irvine shortly before the cars slid out of control and slammed into each other about 10:30 a.m. along a half-mile northbound stretch south of the Jamboree Road exit.

“There was no stopping. It was like a hockey puck on ice,” said California Highway Patrol Officer Dan Lyons, one of five officers sorting out the string of seven separate collisions.

Lyons, who was pulling over the truck about three miles farther north when he was called to the crash, said it was unclear how much diesel fuel leaked onto the freeway. Lyons said a motorist had alerted him to the leaking truck. Some motorists reported smelling diesel fuel immediately after the crash.

Officials said wet driving conditions shortly after a downpour and dense traffic also contributed to the string of crashes.

“A small amount of diesel fuel on the roadway mixed with water--it was just like ice,” said CHP Officer Angel Johnson. She said the crash was under investigation.

Motorists said their brakes were useless as cars began skidding into each other.

“All of a sudden, cars started spinning out in front of me and they jumped on the brakes. I got rear-ended and sideswiped and then I spun out,” said an uninjured motorist from San Clemente whose van was badly dented.

Witnesses said the crash began near the Jamboree Road off-ramp.

Irvine resident David Tokaji sat in a tow truck that was about to haul off his damaged Volkswagen.

“The car in front of me started weaving and I just lost control,” Tokaji said. “I tried to apply my brakes but it was futile.”

It was one of many accidents on slick roads.

Recorded rainfall in the county ranged from .04 of an inch in San Juan Capistrano to .31 in Newport Beach. Anaheim had .06 of an inch; El Toro .16; and Santa Ana .10 of an inch.

“The storm system is rolling out,” said meteorologist Curtis Brack of WeatherData, which provides forecasts for The Times. Brack said it will be sunny and warmer into the weekend, as a weak Santa Ana wind pattern sets in. The forecast calls for highs ranging from the upper 60s to the upper 70s, with a few high clouds and patchy low clouds in the mornings, with sunny skies in the afternoon.

A heavy rain just after 6 a.m. Wednesday contributed to a crash that injured two people and snarled traffic for an hour on North Coast Highway in Laguna Beach, police said. A Jeep Wagoneer driven by Joseph Barbot, 52, of Newport Beach, slid out of control on a pool of water near Emerald Bay and crashed into a car going in the opposite direction, said Sgt. Jim White.

Barbot and the other driver, Linda Kocisak, 48, of Laguna Beach, were listed in fair condition Wednesday afternoon at Mission Hospital Regional Medical Center in Mission Viejo.

Rain accumulating on the flat roof of the Cal State Fullerton Library leaked into the facility’s busy reference section, causing staff to unplug and move computers and remove thousands of books from shelves, after more than a dozen were damaged irreparably by the water.

“We had every wastebasket in the building under the leaks,” said Patricia L. Bril, associate university librarian. “We’re hoping the shelves won’t rust.”

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A rain-loosened boulder crashes into a pickup truck on Ortega Highway. B6