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Heart Mountain Hike

Botanical Journey to the Top of a Geological Mystery

brandon · Jul 5th, 2017

Hiking

Heart Mountain

Geology

Plants

Heart Mountain Hike

Starting Place:

Heart Mountain Trailhead

Heart Mountain is a unique peak for many reasons. Botanically, it is home to one of the greatest concentrations of rare plants on private property in Wyoming. Geologically, Heart Mountain exists because of what could be one of the largest landslides on earth (still debated). Historically, it was a backdrop to a World War II internment camp.

The Hike

Hiking to the top of Heart Mountain (8123’) is a strenuous but rewarding 8.5 mile (round-trip) journey rich in plant-life and views. The Nature Conservancy, the organization to thank for the Heart Mountain Ranch Preserve, has installed interpretive signs along the trail to make it easy to learn all about the rich background of the area.

• Dogs are not allowed

• Before getting to tree-line, there is no shade, so an early start can make it more pleasant. Taking plenty of water (2 - 3 liters) is a good idea.

• The best season to go is early summer or late spring when it is green and the wildflowers are blooming

• The entire journey takes 5 - 6 hours (but can be faster or slower based on pace)

• Horseback riding and mountain biking are not allowed on the summit trail, but are allowed up to the upper kiosk (at the tree-line)

• The interpretive cabin at the trailhead is open 8am to 5pm on Thursday through Sunday from May 1st to October 1st

• To get to the Heart Mountain Trailhead turn off the Powell Highway at the Heart Mountain Interpretive Center and follow the paved road until you see signs guiding you to the Heart Mountain Ranch Preserve.

The Summit

Reaching the top is a rewarding a relief after enduring the switchbacks up to that point. It is a great a spot to relax and take in the views of the Cody area and watch the cliff swallows dive along the cliff edge before making the journey back down the mountain.

Geology

Geologically, Heart Mountain is very out of place. The limestone and dolomite summit formed 400 million years ago when the area was covered by a shallow sea – the limestone contains fossil corals as evidence to its marine past. Yet, it is sitting on top of the 55 million year old Willwood formation which contains fossils of cats and other Eocene mammals. How this block of rock known as the Heart Mountain Detachment got here is still debated, but one popular explanation is that when a nearby volcano collapsed it triggered one of earth’s largest landslides.

Before movement, the Heart Mountain block covered an area of about 450 square miles and almost 5,000 feet thick, weighing trillions of tons. It detached and moved catastrophically down a 2 degree slope and over Dead Indian Hill breaking apart as it slid. Heart Mountain is today located along the structural axis of the Bighorn Basin. Other remnants of the HMD are found dispersed in an area over 1,300 square miles (see figure below). With the maximum velocity of the slide estimated to be from one-third to just under the speed of sound (767 mph), the entire process could have been completed in minutes to a few hours.

— Mark Fisher (geologist)

Willwood Formation (Heart Mountain Foothills)

At 55 million years old, the Willwood formation at the base of Heart Mountain is pretty young in geologic terms. In the late 1800’s and early 1900’s the American Museum of Natural History led paleontological expeditions to the foothills of Heart Mountain to an area known as the Sand Coulee fossil beds and discovered Eocene mammal fossils – including species of cats (source).

Jefferson / Madison Formation (Heart Mountain Summit)

At 400 million years old, the Jefferson and Madison Formations at the summit of Heart Mountain are much older and formed when the area was submerged in a shallow sea.

History

The interpretive signs along the trail tell the stories of the original homesteaders on Heart Mountain such as the Cozzens family and bootlegger Snake River Bill in the early 1900’s. The signs also tell the story of the Heart Mountain internment camp.

In World War II, over 14,000 Japanese Americans were unjustly incarcerated in a camp in the prairie below Heart Mountain. Now this site is home to the Heart Mountain Interpretive Center and it is well worth the visit.

We Japanese and Japanese Americans were incarcerated during World War II in a bleak, forbidden, windswept prairie. The only the of beauty was this majestic butte off in the distance that gave us HOPE!

— Tosho Ito, Former Incarceree

Plants / Wildlife

Besides the great views from the top, one of the best reasons to hike the Heart Mountain trail is the diversity of plant life. Signs along the trail help you identify the numerous species of wildflowers, grasses, and shrubs along the trail. Below is a list of just some of the species you of plants you may encounter.