Ice, Fog Cause 25-Vehicle Crash, Close I-80 : Traffic: Two big rigs jackknife to set off pileup near Sacramento. Eight people are treated at hospitals.

SACRAMENTO —  Subfreezing temperatures produced the Central Valley’s first major traffic pileup of the winter season Thursday as 18 automobiles and seven big-rig trailers collided in the thick fog shrouding an icy interstate causeway slightly west of the state capital.

There were no fatalities but the accident sent eight people to the hospital and closed the Yolo Causeway on Interstate 80 for nearly six hours. I-80 is the major artery between San Francisco and Sacramento.

“It was a very messy affair with cars piling into each other one after another on that part of the roadway,” said California Department of Transportation spokesman Robin Witt.

He said the accident occurred between 3:30 and 4 a.m. when tractor-trailer rigs in the east and westbound lanes jackknifed at virtually the same time. Officials speculated that the driver of the westbound rig saw the eastbound truck jackknife and instinctively hit the brakes, causing his trailer to careen out of control.

In the low visibility, cars and trucks plowed into the trucks, Witt said.

“It all happened pretty much simultaneously. Once everybody started sliding it was just bye-bye, baby,” said California Highway Patrol Officer Don Campbell.

One family told Associated Press they were driving to Sacramento for the holidays when they suddenly hit ice.

“We tried to stop and the car just started sliding,” said Michael Lewis of Oakland. “We hit the car in front of us; otherwise we wouldn’t have stopped. It was real scary.” He said no one in his family was injured.

Witt said the ice apparently had formed very quickly because only a short time before the accident a Highway Patrol car had traveled the same three-mile elevated portion of the interstate and noticed nothing unusual.

Records show that since 1983 there have been only three accidents caused by icy conditions on that stretch of roadway, and none of them resulted in injuries.

Campbell said that by late afternoon most of the injured had been released from area hospitals and no one was reported in serious condition.

The National Weather Service forecast for the Christmas weekend cautions motorists that persistent cold, fog and low clouds will prevail over much of the Central Valley.