A Wyoming mountain collapsed at 50 mph in 1925, and the lake it left is still there

It’s Jackson Hole’s wildest secret

You can see the scar from miles away. A massive gash runs down the face of Sheep Mountain where the entire north side broke loose and crashed into the valley below. That was 1925, and the land never recovered.

The slide dammed a river, created a lake, and left behind a field of rubble you can walk through today. All of it sits just 30 minutes from Jackson, with almost nobody around.

The crowds are all at Grand Teton. This place tells a bigger story.

Fifty million cubic yards came down in seconds

On June 23, 1925, the north face of Sheep Mountain gave way.

About 50 million cubic yards of rock and soil ripped loose and roared into the valley at roughly 50 mph. The debris didn’t just fill the valley floor.

It rode 300 feet up the opposite slope. Warm, wet weather had soaked the hillside and set the whole thing in motion.

It ranks as one of the largest landslides in North America’s recorded history, and you can still read every bit of it on the mountain.

The slide dammed a river and built a lake

All that falling rock blocked the Gros Ventre River cold. Water backed up behind the natural dam and formed Lower Slide Lake, which still sits there today.

Two years later, part of the dam gave way and sent a flood rushing toward the small town of Kelly. The lake and the bare scar on Sheep Mountain haven’t changed much since.

They sit together as a living lesson in how fast the ground beneath you can shift.

You stand right below a raw rock face

A large paved parking area puts you directly under the slide.

Big informational panels tell the story with old photographs and maps, but the real draw is the view straight up. The raw rock face towers above you, exposed and broken.

The mountains here are geologically old, but landslides and other forces keep reshaping them. You won’t pay a dime to see it, and the site stays open all day long.

No tickets, no reservations, no gift shop.

A short loop trail crosses the debris field

An easy loop of about six-tenths of a mile winds right through the rubble the slide left behind. The path crosses jumbled rock and patches of new plant growth that have slowly taken hold over the last century.

Signs along the way explain how the whole thing happened. Partway through, you get a clear look down at Lower Slide Lake below.

The trail is gentle with little climbing, so most people can handle it without any trouble.

Red and tan rocks unlike anything in the Tetons

The slide ripped open a jumble of reddish and tan rock that looks nothing like the gray granite of the Teton Range to the west.

Red rock cliffs and canyon walls rise along the road nearby, and the mix of colors draws photographers from all over. These are ancient layers, now tilted and broken, telling a story that goes back millions of years.

The whole setting feels like a different world from the famous peaks just a short drive away.

Trout fishing on a lake the landslide built

Lower Slide Lake holds cutthroat and lake trout, and you can cast from a boat or find a spot along the shore. You’ll need a Wyoming fishing license before you wet a line.

Quiet evenings on the water are hard to beat, with the mountains reflected on the surface and almost no one else around.

The Gros Ventre River below the lake also runs good trout water, so you can fish both in the same day if you have the time.

Drowned trees still stand upright in the shallows

Paddle a canoe or kayak onto the calm water and you’ll see something strange.

Trees drowned when the lake formed more than a century ago still stand upright in the shallows, bare trunks rising straight out of the surface.

You can glide between them for a view you won’t find on any other lake in Wyoming. A boat launch at the Atherton Creek area gives you easy access.

Below the lake, the river turns to rough whitewater best left to experienced paddlers.

Elk, moose and bison roam the valley floor

Early morning and evening bring the best wildlife sighting chances here. Elk, moose and bighorn sheep move through the valley regularly.

Bison sometimes gather near the road and block traffic entirely, so give yourself extra time. Bears live in the area too, which means you should stay alert and keep your distance.

Cottonwoods and willows along the river pull in moose and birds, making the drive in almost as good as the destination itself.

Camp right on the lakeshore at Atherton Creek

Atherton Creek Campground sits on the shore of Lower Slide Lake, and the paved road in winds through aspen stands with river views the whole way. Campsites work for tents and smaller trailers.

You can launch a boat or grab a fishing rod without leaving camp.

The spot is peaceful and quiet, but Jackson and Grand Teton National Park are both close enough to reach in under an hour. It’s a solid base if you want to explore the whole valley.

Red rock walls line the drive from Kelly

The Gros Ventre Road follows the river east from the small town of Kelly, and red rock walls and open western country line both sides. Big views back toward the Teton peaks open up behind you as you go.

The route draws far fewer cars than anything in the park, and that’s the whole point.

Parts of the road turn to gravel farther out and can get rough, so check conditions before you push too deep into the backcountry.

Sheep Mountain looks like a sleeping figure from town

From Jackson Hole, Sheep Mountain takes on a different shape entirely. Its cliffs look like a person lying on their back, which is why locals call it the Sleeping Indian.

The peak rises above 11,000 feet at the edge of the Gros Ventre Range, and its colorful summer cliffs stand out against the sky.

The northern end of that ridge is exactly where the great slide broke free, tearing the face right off the mountain and sending it into the valley.

No cell service, no crowds, no complaints

The whole area sits inside the Bridger-Teton National Forest, and it rewards you with solitude that Grand Teton can’t match. You come here for geology, wildlife and wide-open quiet.

There’s no cell service and no drinking water on site, so pack everything you need before you leave Jackson. This corner of Wyoming doesn’t try to impress you with amenities.

It just gives you raw land, a wild story and the kind of silence that’s hard to find anywhere near a national park.

Explore the Gros Ventre Slide near Kelly, Wyoming

You can see the landslide for yourself at the Gros Ventre Slide Geological Area, located off Gros Ventre Road past Kelly, about a 30-minute drive from the town of Jackson. The site is free to visit and open all day, year-round.

A large paved parking area, informational panels and the short interpretive trail are all waiting when you arrive.

Bring water, snacks and a full tank of gas, and check the official website for current road conditions before you head out.

This article was created with AI assistance and human editing.

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