Heavy snowfall is forecast for the Sierra Nevada and Lake Tahoe region this weekend as a series of storm systems move into the western US. Snow levels are expected to drop to around 6,000 feet, with higher elevations potentially receiving multiple feet of snow by early next week. Ski resorts could see significant accumulation, while lake level areas may receive several inches. Travel conditions on major routes like Interstate 80 and Highway 50 are expected to deteriorate due to snow and reduced visibility.