Back in 1905, the Colorado River, swollen with heavy rainfall and snowmelt, surged into a dry lake bed along California’s San Andreas Fault and formed the Salton Sea. The flood waters submerged most of the small town of Salton, along with nearby tribal lands. The inundation also covered a key, seismically active stretch of the San Andreas Fault’s southern tip in silt, hiding evidence of its potential volatility.