San Francisco ? A storm spread rarely seen snow and sleet across the San Francisco area early Saturday, and two people were killed in a 28-vehicle pileup on slippery Highway 101 just north of the Golden Gate Bridge, authorities said.

Cars were scattered along a 350-foot stretch of the highway. The highway’s northbound lane just north of the Waldo Tunnel remained closed by late morning, causing major traffic backups on the Golden Gate Bridge.

The driver of the car in which the two victims died was arrested on suspicion of driving under the influence but was released after a blood analysis concluded he was not drunk, Ziese said.