http://stream.publicbroadcasting.net/production/mp3/knau/local-knau-877781.mp3
Flagstaff, AZ – Earthnotes: Quicksand
About eight centuries ago, the ancestors of today's Hopi people built several villages along the Little Colorado River near present-day Winslow. They called the place "Hom lovi," meaning "place of the little hills," and the ruins they left behind became an archaeological landmark.
The location of Hom lovi is no coincidence. It's among the few sites along this stretch of the Little Colorado that lack quicksand. Southwestern washes and rivers are rich in quicksand, thanks to the sand blown, washed, and eroded into streambeds from rocks that millions of years ago formed dunes and beaches.
Quicksand forms when a steady stream of slow-moving water arises below a sand deposit. This upward flow polishes irregular sand particles until they are as smooth as ball bearings. Once that happens, the slippery granules can't support much weight.
Heavy objects can sink almost immediately in quicksand. If you're caught in quicksand, reduce your risk of drowning by spreading your arms and legs out and lying on your back to distribute your weight, rather than standing upright.
During storms, otherwise dry and harmless sand washes like the Little Colorado may become deadly. Cows, sheep, people, and even vehicles have been swallowed whole by quicksand.
Around Hom lovi and Winslow, however, much of the riverbed is free of quicksand. Modern-day drivers who cross the river on Interstate 40 are simply following in the footsteps of those who learned how to coexist with a fickle river many centuries ago.
-Richard Mahler