Landslides Created America’s Youngest Mountain Range – It’s Now a Wildlife Paradise in Wyoming

Crown Jewel of Wyoming’s Wilderness

Grand Teton National Park sits in northwestern Wyoming. Huge glaciers and earthquakes shaped the sharp peaks of the Teton Range that rise 7,000 feet straight up from the valley.

Now covering 310,000 acres, it connects to Yellowstone National Park through the John D. Rockefeller Jr. Memorial Parkway. With over 3 million visitors each year, come discover one of the largest unspoiled natural environments of its kind in the middle latitudes of Earth.

A 1925 Landslide Formed a Lake

The Gros Ventre landslide on June 23, 1925, created Lower Slide Lake. It was caused mainly by heavy snowmelt, rainfall, and tremors, not a major earthquake.

The landslide moved 50 million cubic yards of rock down Sheep Mountain, blocking the Gros Ventre River. The dam it formed was over 200 feet high and 400 yards wide, creating a lake.

In 1927, part of the dam failed, causing a flood that destroyed the town of Kelly, Wyoming.

Underground Rivers Shape the Park’s Features

Glacial meltwater contributes to late-season flows in streams like Cascade Creek and Leigh Creek. On the eastside, the Gros Ventre Slide area contains limestone and shale layers that interact with subsurface water systems.

The Death Canyon Limestone Member in the Teton area was deposited in clear water during the Cambrian period, forming part of the Gros Ventre Formation. Taggart Lake is fed by surface runoff and Darby Wind Cave, located west of the Tetons, is an example of a cave dissolved out of limestone by underground water.

2.7 Billion Years of Geology

Grand Teton National Park offers a rich geological history, with the Teton Range’s cliffs and valleys. The oldest rocks in the park are over 2.7 billion years old, consisting of gneiss and schist.

Fossils of trilobites, brachiopods, and ammonites, preserved in limestone layers, date back 500 million years when an ancient sea covered the area. Glacier melt later shaped valleys and moraines, carving formations like the Snake River and Jackson Lake.

The smallest glaciers, such as Teepe Glacier, may disappear entirely within decades due to their rapid melting rates.

Native Americans Used the Mountains

The National Park Service recognizes 24 associated tribes connected to the park’s lands and resources.

Human presence in the area dates back over 11,000 years, with evidence of Paleo-Indian hunter-gatherers who utilized obsidian from nearby Teton Pass for tool-making. ​The Spanish Diggings in eastern Wyoming are one of the largest known prehistoric quartzite quarrying sites, east of the Tetons, dating back about 10,000 years.

The Teton goldenweed

The Teton goldenweed is a tough little plant with yellow flowers that doesn’t grow anywhere else in the world. It’s been here since the last ice age (about 10,000 years ago).

It can survive some of the harsh conditions, preferring rocky, well-drained soils at elevations from 7,500 to 11,000 feet. The plant adapted to life in extreme heights by growing close to the ground to avoid winds that blow up to 100 miles per hour.

Wildlife That Thrives in the Biodiversity Hotspots

Grand Teton National Park is a vital stopover for migratory birds and supports over 300 bird species. If you’re lucky, you might catch a glimpse of the majestic bald eagle which nests in the park, and the peregrine falcon, known for its incredible speed.

Home to 16 large mammal species, estimations include 400 individuals in the Jackson Hole moose herd, bison (Bison bison), black bears (Ursus americanus), and grizzly bears (Ursus arctos horribilis).

Large predators like grizzly bears are actively monitored, while the elk and bison populations are carefully managed.

Plants from the Ice Age in Hidden Valleys

Deep in Death Canyon and Cascade Canyon, some plants still grow in special cold spots, usually 1000 miles farther north, sharing almost the same genetic makeup as their relatives in the Arctic.

In these secluded areas, over 1,000 vascular plant species thrive, many of which have remained unchanged since prehistoric times.

The valley floors of Jackson Hole are blanketed with silvery-green big sagebrush, while Narrowleaf cottonwood and various willow species grow along the Snake River and its tributaries, creating vibrant green ribbons across the landscape.

Sound Travels in Unusual Ways

Some places in the park have strange sound patterns because of how cold and warm air trapped between the valley and mountain peaks. In Cascade Canyon and Death Canyon, sounds can travel up to three miles through these natural sound channels.

These sound patterns work best on quiet winter mornings when temperatures drop below 20 degrees Fahrenheit. The park’s valleys and canyons create natural amphitheaters that amplify elk calls during mating season.

Elk use these sound channels and their calls travel five times farther than usual.

Special Trout Have Evolved in Mountain Lakes

Snake River and its tributaries between Jackson Lake and the Palisades Reservoir hold groups of fine-spotted cutthroat trout that have adapted to life in cold water that stays below 60 degrees Fahrenheit year-round.

Some populations are thought to have been in the region for more than 14,000 years, surviving the Ice Age. These trout are characterized by hundreds of small spots covering their bodies, unlike the larger spots found on Yellowstone cutthroat trout.

The Butterflies that Live in the Mountains

The park is home to an estimated 10,000 insect species, with over 60 butterfly species documented in Teton County alone.

The Teton Arctic butterfly, which lives above 10,000 feet, has dark wings that soak up 90% more sun than butterflies living at lower heights. Back in 2016, McCombs studied the genetic structure of Parnassius clodius butterflies in Grand Teton National Park and their role as indicators of environmental changes.

Ancient Tree Fossils Narrate the Past

Mount Moran contains fossilized remains of forests that grew 50 million years ago. These stone trees, including ancient sequoias and magnolias, show that this area once had weather similar to what Georgia has today.

Scientists studying these stone trees have found 65 types that no longer exist and learned how the climate changed over time. The fossils prove that this area changed from a warm, humid place to the cold mountain environment we see today.