Overview
On June 23, 1925, roughly 50 million cubic yards of rock, soil, and forest broke loose from the north face of Sheep Mountain in the Gros Ventre Valley east of Jackson and buried the Gros Ventre River valley under a debris field two miles long, a half-mile wide, and several hundred feet deep. The landslide happened in less than two minutes. The debris dam it created backed up the river for miles, forming Lower Slide Lake. Two years later the dam partially failed, and a wall of water swept down the valley and destroyed the small town of Kelly, killing six residents.
The Gros Ventre Slide Interpretive Trail visits the site of this event via a short one-mile walk through the consolidated debris field. Interpretive panels explain the geology of the failure (a combination of water-saturated clay layers and oversteepened terrain), the formation of the lake, and the 1927 flood. The hike is less about the trail itself and more about standing inside a genuine geological event site that remains visible and legible on the landscape a century later.
The Route
From the small parking pullout on Gros Ventre Road, the trail descends slightly onto the debris field and follows a well-marked path through the slide material. The terrain is irregular and rocky underfoot, composed of sandstone blocks and consolidated sediment from the original slope. Interpretive signs at intervals explain what you are standing on and where to look for specific features in the surrounding landscape.
The trail ends at a viewpoint overlooking Lower Slide Lake and the remaining slide deposit across the valley. Sheep Mountain (also called Sleeping Indian) dominates the southern skyline. The scar on the mountain face where the slide originated is still clearly visible. Return the way you came. The whole walk takes 30 to 45 minutes including time at the interpretive signs.
The trail surface is rocky and uneven throughout. Sturdy footwear is more useful here than on a typical easy trail. There are no steep climbs, but the irregular footing requires attention.
When to Visit
The trail is accessible from May through October, and sometimes later. May visits may find the road muddy and the lot soft; call the Jackson Ranger District if you plan an early-season visit. Peak summer (July through August) is warm and dry. Fall visits in September and October offer quieter conditions and excellent light on the surrounding range.
This is one of the few nearby short trails where wildfire smoke matters less than on longer mountain hikes — the interpretive walk is brief and the viewpoint is in an open valley. Even on smoky days, the slide site is an interesting stop. Check Checking Conditions Before You Go for current road and weather information before heading out on Gros Ventre Road.
What to Bring
The trail is short enough that minimal preparation is needed: water, good footwear for irregular terrain, and sun protection (the debris field is fully exposed). No water source exists at the trailhead or on the trail. Cell service is absent on the Gros Ventre Road corridor.
The Gros Ventre Valley has active moose habitat and is within the Greater Yellowstone grizzly range. Bear spray is a reasonable precaution even on a short trail. Dogs are allowed on leash.
Getting There
From Jackson, take US-89 north to the Gros Ventre Junction (near the town of Kelly). Turn east on Gros Ventre Road and follow it approximately 10 miles to the slide area parking pullout on the right side of the road. The road is paved for the first several miles and transitions to gravel. Drive time from Jackson is approximately 25 minutes.
Atherton Creek Campground is about 2 miles further east on the same road and provides overnight access to the valley. For the broader forest overview, see Bridger-Teton National Forest. For a neighboring trail with very different scenery, see Cache Creek Canyon Trail just east of downtown Jackson. For responsible travel practices in this fragile landscape, review the Leave No Trace 7 Principles.