I found one (freewheeling, not radio/atomic) in a dry rocky wash halfway up a mountain in the Desolation Wilderness, CA, a couple of decades ago. It was half-buried -- it had obviously been dropped at least a year earlier, and washed down the cwm in spring thaws. You could barely read the face. We took it back to the tent, and the next morning its tinny alarm went off at 6:30am.