A dangerous storm system is slamming California, with meteorologists at the National Weather Service warning of imminent “widespread flooding, impassible roads, mudslides/landslides [and] rapid rises in rivers/creeks.” The system, which prompted the Weather Service to take the unusual step of urging residents to have “go bags” at the ready and prepare insurance documentation in advance, is set to unleash its harshest conditions Wednesday night into early Thursday.Virtually the entirety of Northern and Central California is under flood watches and high-wind warnings, with damaging gusts to 60 mph possible. Strong to severe thunderstorms could be in the offing as well, in...