A massive fissure that has mysteriously appeared on the flanks of the Bighorn Mountains in Wyoming is a slow-moving landslide, possibly triggered by excessive precipitation combined with moisture from a nearby spring, a state geologist said on Friday.
The mass geologic movement in a remote area came to light a week earlier when commercial hunters in Wyoming discovered it and posted photographs and commentary on their firm's Facebook page, sparking a flurry of online interest.
The hunters from SNS Outfitters and Guides said in a posting that a device used to measure distance for hunting purposes suggested the fissure was 750 yards (meters) long and 50 yards wide.