Higher elevations of Northern California were hit by heavy snowfall overnight, prompting avalanche warnings, as the region braced for a week of intense weather. The National Weather Service said it expected four to five feet of snow in some Sierra areas and encouraged drivers to avoid mountain roads. One location, Kingsvale, got 23 inches of snow in just the last 24 hours. The Sierra Avalanche Center on Monday issued a warning for some areas hit by heavy snow. “Human triggered wind slab avalanches occurred yesterday in a variety of locations.