Shasta Lake, California’s largest reservoir, filled to nearly 100 percent capacity in May 2023, reaching levels not seen for four years. Since 2019, a prolonged period of extreme drought resulted in dwindling reservoir levels. In the early months of 2023, heavy rains and meltwater from an above-average mountain snowpack caused a notable turnaround. Read more about Shasta Lake, California’s largest reservoir, filled to nearly 100 percent capacity last month