This picture from NASA’s Earth Observatory shows how much land in California’s Central Valley is sinking, due primarily to the drawing of groundwater during periods of drought. Heavy rains have fallen on many parts of the state this winter, but the image above is a reminder of the lingering effects of drought, even in wetter times. As the legend at the bottom of the picture suggests, the yellowest areas are those with the greatest degree of subsidence (the term for sinking land) and the bluest areas are those with the least.