Complex sentence: A surge went down the canyon-washing out 2 older suspension bridges-just below the Long Canyon influx and at the Spanish Dry Diggings crossing near Greenwood-and then washed out the State Hy 49 bridge over the American River just below Auburn.
Split into simpler sentences: A surge went down the canyon-washing out 2 older suspension bridges below the Long Canyon influx and at the Spanish Dry Diggings crossing near Greenwood. It then washed out the State Highway 49 bridge over the American River just below Auburn.