Possible tornado causes damage in Montebello, Los Angeles.

The National Weather Service is investigating the possibility that a tornado hit Montebello, California, after a period of wild weather across the state that brought heavy winds and warnings of tornados and landspouts. The region largely fared better than the San Francisco Bay Area, where at least five people were killed, although roadway flooding, debris flows and strong winds were reported. Flood watches will remain in effect through Wednesday afternoon in areas ranging from Oxnard to San Diego, including much of the L.A. Basin. A winter storm warning is also in effect until 5 a.m. Thursday in the San Bernardino Mountains, where 60 mph wind gusts and up to 14 inches of fresh snow are possible.