Kelso Dunes

The Kelso Dunes sing. When the sand avalanches down the slip face — and only when conditions are exactly right — the dunes emit a low-frequency boom somewhere between 70 and 105 Hz, a note like a bass violin or a distant propeller plane that can carry for miles and last for minutes. There are only about forty places on earth where dunes do this, and only three in the United States. Kelso is one of them.

Travelers have been reporting booming sand for fifteen hundred years — medieval writers assumed it was superstition until the nineteenth century, when explorers began documenting it seriously. Darwin heard it in Chile. The physics wasn't worked out until the twenty-first century: the sound is the dune itself acting as a waveguide, the avalanching sand resonating in a surface layer like an instrument — the dune's shape selecting the note the way a violin's body does.

The dunes themselves are the wreckage of a lake. The Mojave River carried quartz and feldspar out of the San Bernardino Mountains for three million years into Lake Manix; when the lake catastrophically drained twenty-five thousand years ago, the exposed sediment blew southeast until the Granite and Providence Mountains trapped it into a six-hundred-foot pile of singing sand — one of the strangest instruments on earth, still being played every time the wind moves the slip face.