The Bonneville Salt Flats are a striking expanse of desiccated salt in an even more expansive desert. Visitors will find a region nearly devoid of vegetation and utterly flat. The watery mirages at the horizon, however, are an echo of not-so-distant past, when icy waters filled this basin 1000 feet deep and wooly mammoths roamed its forested shores. Waves of this ancient lake rolled along its coast, rounding stones and building up a shoreline, even as humans were first crossing the Bering Strait into North America.
Eventually, when the Earth tilted back towards the warming rays of the sun, the great ice sheets of this Ice Age melted, the climate warmed, and rains that had kept Lake Bonneville filled moved elsewhere. Massive floods burst from the lake periodically as new drainage channels opened. When the lake stabilized, waves again began working shorelines into the hillsides at the new water level. Eventually, the lowest drainage channel was cut off and the lake sat for thousands of years in the dry heat, evaporating slowly, but inexorably. Salts from the ancient rocks of the surrounding mountains dissolved in rainwater and trickled into the lake. With nowhere to go, they became more and more concentrated, until they crystalized in the last remaining pool of the once-great lake.