A powerful storm blasted the Sierra Nevada with waves of torrential rain and heavy snowfall on Sunday, leaving a vast swath of California bracing for potentially disastrous floods, avalanches and mudslides. The latest weather comes just days after the mountains around Lake Tahoe and Yosemite National Park received several feet of snow over the span of a week. At Mammoth Mountain, a ski resort bordering Yosemite, the 11,000-foot peak got 84 inches of snow in just two days.