SACRAMENTO—Powerful storms pummeling parts of California were expected to hit the state’s southern mountain ranges on Thursday, raising fears of mudslides on hills stripped bare from last year’s wildfires. Winds of up to 120 mph swept through the northern Sierra Nevada mountains near Lake Tahoe when the storms there peaked earlier this week, and the capital city of Sacramento was still grappling with power outages and downed trees on Thursday. The National Weather Service on Thursday issued winter storm warnings for mountainous areas in Los Angeles, Ventura, and Santa Barbara Counties, and flood advisories for much of the agricultural Central Valley. In Monterey County along the Central Coast, several debris flows forced evacuations on Wednesday, heightening concerns that last year’s fires could be followed by dangerous mudslides as heavy rains continue. The 2020 fire season was one of the worst on record in the most populous U.S. state, burning 4.3 …