As the West descends deeper into drought, climate and water experts are growing increasingly alarmed by California’s severely shriveling reservoirs.

On Monday, Shasta Lake — the largest reservoir in the state — held a scant 1.57 million acre-feet of water, according to the U.S. Bureau of Reclamation, or about 35% of its capacity.

A series of satellite images captured by NASA show just how dramatically the water level has fallen.