Utah
Natural bridges such as Rainbow Bridge differ from arches because they are primarily carved by water, while arches are formed by wind and freeze-thaw cycles.
If wind and water are nature’s sculptors, then sandstone is the ultimate medium—more malleable than clay, more graceful than marble. Over millions of years, trickles of water and wisps of wind can have a profound impact on sandstone. One of the most dramatic sandstone sculptures in the Southwest is Rainbow Bridge, an arc that spans 234 feet over a waterway, and one of the largest natural bridges in the world. Natural bridges differ from arches in that they span a waterway or are primarily water-formed. From the air, Rainbow Bridge can be seen reaching up and over Bridge Creek in the far southern reaches of Utah.
The rocks that make up Rainbow Bridge were deposited during the time of the dinosaurs, when this part of North America was covered by extensive sand dunes, left from an inland sea. These sediments, more than 1000 feet thick, were later reburied under 5000 feet of other sediments. The accumulated weight compressed the sand into Navajo Sandstone, an especially hard type of sandstone that forms sheer cliffs, arches, and bridges all over the Southwest.
Millions of years ago, small Bridge Creek began flowing toward the Colorado River, finding its way through the softer layers of rock and going around the harder layers. When it met the fin of Navajo Sandstone that would become Rainbow Bridge, the creek veered around it, creating a hairpin turn. Turbulence generated in the flowing water by the sharp turns in the creek bed began eroding alcoves in the front and back of the fin. Over time, Bridge Creek wore away a tunnel through the lower part of the fin, leaving the upper bridge spanning the canyon.
Rainbow Bridge has long been held sacred by the Paiute, Navajo, Ute, and Hopi people, who call it Nonnezoshe, “rainbow turned to stone.” For centuries, the bridge was protected by its remote and inhospitable location. But in 1963, the flooding of Glen Canyon to create Lake Powell opened access to the bridge to anyone with a motorboat, although low lake levels in recent years have lengthened the hike up the canyon to reach the bridge.
You might fly over Rainbow Bridge on a scenic charter flight of Lake Powell. The bridge is located on the south shore of the lake, down Forbidding Canyon, the lower reaches of which are navigable by boat during high water.
