Water rushing from a spillway at the Jackson Lake Dam, a concrete and earth-filled dam in Grand Teton National Park in northwest Wyoming. (Other relatively small portions of the scenic park spill into Montana and Idaho.) The Snake River emerges from the dam and flows about 800 miles (1,287 km) through Wyoming, Idaho, Oregon, and Washington to its mouth on the Columbia River in eastern Washington. Photo by Carol Highsmith, 2015.