The drought-busting snow and rain in the mountains around Lake Tahoe have pushed the lake to its highest level in more than a decade. After five years of drought, the alpine lake atop the Sierra Nevada now has enough water to fill downstream reservoirs and meet the Reno area’s needs for at least two years, hydrologists say. “We are basically going from one extreme to the other in two years,” said Bill Hauck, senior hydrologist for the Truckee Meadows Water Authority.