Heavy snow blanketed parts of the Sierra Nevada mountains of Northern California on Thursday, December 12, prompting weather forecasters to warn of treacherous travel conditions in the area.Footage posted to X by UC Berkeley Central Sierra Snow Lab shows snow piled up at their base in Soda Springs, California, on Thursday morning. The lab said they expected up to 12 inches of snow in the next 24 hours, and up to 4 feet total by Sunday.A second wave of rain and mountain snow was forecasted in the region on Thursday evening, according to the National Weather Service. Credit: UC Berkeley CSSL via Storyful