The Gros Ventre Slide
7 miles north of Jackson on U.S. Highway 89; turn right & travel 11 miles on the Gros Ventre Rd.


On June 23, 1925, one of the largest fast-moving landslides in generations occurred near the village of Kelly, Wyoming. In just three minutes, huge amounts of rock and debris cascaded down the north slope of Sheep Mountain, changing the area forever.

Hurling down the slope at 50 m.p.h., the mile-wide slide carried 50,000,000 cubic yards of debris. The mass rode 300 feet up the opposite slope, blocked the Gros Ventre River, and formed a five-mile long body of water known today as Lower Slide Lake. The piles of debris seen today contain large chunks of Tensleep Sandstone, along with remnants of the original forest.

Throughout the years, many people have wondered what caused this tremendous slide. Three primary factors are thought to have contributed to the unusual event:

  1. heavy rains and rapidly melting snow saturated the Tensleep Sandstone, causing the Amsden Shale rock layer on Sheep Mountain to become exceptionally slippery;

  2. the river, cutting through the sandstone, produced a “free side” with no extra support holding it in course;

  3. swampy pools with no outlets, on top of the mountain, indicating water-saturated soil.

Earthquake tremors (which were occurring) added to these already unstable factors and could have precipitated a landslide.

William Bierer, a long-time native to the area, predicted a slide in the near future. Convinced of the validity of his theory, Bill sold his ranch on Sheep Mountain to Guil Huff, an unsuspecting cattle rancher, in 1920. Bierer died in 1923 before his prophecy became reality.

Two years later, on the afternoon of June 23, 1925, Guil rode horseback down the river to the north side of Sheep Mountain where he had heard loud rumblings. He arrived at 4 p.m., in time to witness 50 million cubic yards of land mass descending rapidly toward him. He and his horse escaped the impact by a mere 20 feet. Along with Guil, two other men witnessed the phenomenon of nature — Forney Cole and Boyd Charter.

In a matter of minutes, debris covered 17 choice acres of the Huff ranch. Guil, along with his wife and daughter, escaped. Ranger Dibble took Mrs. Huff and the child to safety at the Horsetail Ranger Station. By 4 a.m. the next morning, the Huff house was standing in 18 inches of water. By June 29, after heavy rains caused the dam to fill and overflow, the Huff house was floating in the lake, to be joined by the ranger station on July 3.

Ranger Dibble moved his family to Kelly, Wyoming, where he kept a wary eye on the slide dam. A man-made dam has a built-in spillway so that the waters cannot top the dam, erode, and breech it. The slide dam, made by nature, was not equipped with a spillway.

Engineers, geologists, and scientists came to the area to study the slide; they determined that the dam formed as a result of the slide was permanent and safe. Most of the local people accepted that decision and ceased worrying about a possible disaster, especially when the spring runoff in 1926 passed with no major problems.

The winter of 1927, however, was one of the most severe ever recorded in the state to that time. When spring arrived, the unusually deep snowpack melted quickly, aided by days of rain. On May 17, water began spilling over the low places of the dam. The Gros Ventre River was rising.

Ranger Dibble and Jack Ellis, along with some other men, were poling driftwood and floating debris away from lodging against the Kelly bridge and endangering the structure. Suddenly Ranger Dibble saw a hayrack—one that had been in the lake above the dam since 1925—floating down the river.
He and Ellis jumped into Dibble’s Model T and drove toward the dam to assess the situation. On the way, they were met by the main thrust of water and debris. The top 60 feet of the dam had given way under the pressure of the excess water.

Dibble and Ellis turned around and headed for Kelly to warn the residents of the impending danger. By the time they arrived, the people had only 15 minutes in which to flee to safety.

Despite the warning, Henry (“Milt”) Kneedy refused to believe the water was coming, and would not permit his wife and foster son, Joe, to leave. Ranger Dibble tried to rescue little Joe, but he got away and ran back to his mother. Later, Joe was reportedly seen clinging to the top of a barn floating down the river. The Kneedy family died in the flood.

Through field glasses, a rancher watched May Lovejoy and her sister, Maude Smith, load their wagon with valuables and drive off, but the horse became frightened and raced out of control toward the oncoming water. A wall of water rolled the wagon over and over. May’s body was never found. Maude’s body was retrieved after the water subsided.

Max Edick and Clint Stevens were trying to save their livestock when the water came. Quickly, they climbed to the top of a small chicken coop. Though Clint managed to jump onto a passing hayrack, he did not survive. Max was swept into the swift water. He somehow managed to catch hold of a tree branch, and was later found alive.

By 4p.m. the water receded. Six lives had been lost in the tragedy. Along with the human lives lost, hundreds of domestic animals perished. Property damage was estimated at $500,000. The little town of Kelly was almost completely obliterated.
As a result of the flood, Kelly was not awarded the special recognition of becoming the county seat. That distinction was given, instead, to Jackson.

Lower Slide Lake
This lake was formed when the landslide dammed up the Gros Ventre River. Many of the trees that once grew along the river were submerged, and today the tops of several of these trees can be seen at the far side of the lake.

Lake trout, Snake River cutthroat, mountain white fish, Utah suckers, and Utah chubs inhabit the lake.

Upper Slide Lake, formed long before man roamed this area, has no connection with the Gros Ventre Slide disaster.

Trees On The Slide
Several of the trees at the base of the slide are growing at abnormal angles. These trees were swept downhill with their roots still intact in the soil. They came to rest in the position in which you see them today.

It is interesting that trees over 40 years of age succumbed to the shock of that traumatic transplanting, while the younger trees were able to adapt and continue growing.

In the crystal clear water of the lake, some trees can still be seen standing erect where they were transported by the slide more than half a century ago.

Trees found in the Gros Ventre area are lodgepole pine, Englemann spruce, subalpine fir, Douglas fir, Rocky Mountain juniper, and aspen.

Life On The Rocks
Pikas, the smallest members of the rabbit family, also known as coneys, range from approximately 6 to 8 inches in length. They are grayish brown in color. These small herbivores do not hibernate; instead, they store little piles of dried plants under the snow for use in winter. Pikas make their homes under the rocks that were transplanted in the slide. They can be heard “bleating” as they travel along their trails under the rocks.

Lichens are plants composed of two different organisms: microscopic green or blue-green algae and colorless fungal threads. Lichens grow on the surface of rocks. Their colors vary from black to gray, rust, green, and brown. These small plants are important because they break rocks down into small pockets of soil on which other plants will grow.

Article courtesy of National Forest Service

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