The series of storms over the last few weeks in the Sierra Nevada have been very good to Lake Tahoe. According to the National Weather Service, the lake has gained about 33.6 billion gallons of water since Jan. 1 — and the lake has risen about one foot. It’s a big turn around from just a few years ago, when the drought had Lake Tahoe water levels reaching record lows. After a lull Monday, more snow is on the way for the Sierra through Thursday.