KUSA – A crack that started developing in late September on a Wyoming ranch is now about the length of six football fields.

The crack, which is about 50 yards wide, is located 40 miles south of Ten Sleep.

"We don't really know what caused it, or if it's done falling," Sy Gilliland SNS Outfitter & Guides said. "One of my hunters stumbled on it when he was hunting there Oct. 1."

"And the next time anybody went out there, a few weeks later, there it was, this huge slide or crack or whatever it is," Gilliland said. "I don't really think anyone knows what happened out there, all of a sudden it was just there. I think the reason it's so fascinating is it's so big. And it doesn't make any sense, where it happened it's just like the ground opened up, and the size of it is just huge."

Hunting guides scouting for antelope discovered the massive tear in the ground, which is hundreds of yards long and at least 100 feet deep in some places. Employees of SNS Outfitter & Guides service took photos of their discovery and then got busy with hunting season. When they came up for air last week, they posted the photos on the company's Facebook page and watched the world react.

Experts say water running through the hillside loosed the dirt, and gravity did the rest. It poses no danger to people or structures — it's on state-owned land in the middle of a private cattle ranch. SNS owner Sy Gilliland decided Saturday that he needed to see the crack for himself, and escorted a USA TODAY journalist across the private property to see it.

His immediate reaction? Unprintable but understandable. His more considered reaction: "This is really big. I'm pretty much in awe. The end of the hill just fell off."

The wet spring in Wyoming meant more water than usual saturated the ground. There's no oil drilling, fracking or other development occurring for more than 20 miles in any direction, and with no recorded earthquakes in the area, experts say it appears simple physics is responsible: The dirt got wet and slid. The guides who discovered the crack say it's slowly getting bigger, as isolated towers of dirt in the middle collapse.

"It certainly shows the power of the Earth," Wyoming state geologist Tom Drean said.

Drean said slides like this happen regularly in Wyoming, although they're usually smaller and happen in the spring. But he pointed out the state has a long history of unique geography, from the Grand Tetons to Yellowstone National Park's Old Faithful geyser.

"Wyoming is a geologic wonderland, and this is just an example of that wonderland," he said.

(© 2015 KUSA)