0.0

Begin at Lander; junction of Highway 287 and Route 789 on the East end of town. Proceed West on 789.

0.6

5th and Main Street; turn South on 5th St.

1.3

5th and Fremont St.; turn West, then South through Sinks Canyon.

3.0

Hills West of the highway expose the reddish-colored sand and mudstones of the Chugwater Formation.

3.9

The Chugwater Formation

4.9

Rise in topography.

7.1

Sinks - these are sinkholes eroded into the limestone bedrock by acid groundwater.

These canyon walls, consisting of the Ordovician Bighorn Dolomite, are used for climbing practice by the National Outdoor Leadership School, which has headquarters in Lander.

8.4

These cliffs of the Bighorn Dolomite have prominent talus piles at their bases. Talus is rock debris resulting from weathering of rock, mostly due to shattering by freeze-thaw activity.

Freeze-thaw action, or frost wedging, is the result of water freezing in fractures in the rock. The volume increase of freezing water breaks apart rock just as water left in a container outside in the winter will burst the container.

In cold and dry climates, frost wedging is often the most important agent in breakdown, or weathering, of rocks.

9.0

This boulder field at the base of the canyon is the result of glacial activity. These boulders are examples of the coarse rock that glaciers carry, and later drop on the landscape. Large rocks of this sort are called glacial erratics. A ridge or mound of unsorted rock debris dumped by a glacier is called a moraine.

11.4

Bruce's Campground at base of Loop Road, stop and turn around.

0.0

Return to Lander.

3.0

Formation

3.9

Chugwater and stratigraphic units above it.

4.9

Rise

7.1

Sinks

8.4

Cliffs and alluvial fan/talus

9.0

Another field of glacial erratics.

10.1

5th and Fremont St. Drive East to junction.

10.7

Junction - Highway 287/Route 789 (5th and Main streets)

0.0

Highway 287; drive West, then North toward Fort Washakie.

12.6

Hills West of highway.

15.0

Fort Washakie hill, East of road.

The flat top of the hill is typical for a terrace. A terrace is a former floodplain of a river that occupied this position before cutting down to its present level. Terraces are evidence of uplift or other changes that cause rivers to switch from depositing sediments to eroding their channels.

18.2

Hills on East side of highway. The Chugwater Formation is exposed here.

18.5

Hills and possible fault, East side of road.

18.7

Hills on East side of highway.

19.9

The hills on the West side of the highway expose the Eocene Wind River Formation.

30.8

Hills East and West of road near junction.

Junction of Highways 287 and 26; turn West on Highway 26.

31.9

Cliffs above Wind River.

33.9

Same cliffs better angle.

40.3

Crowheart Butte sign.

Crowheart Butte is made of the Eocene Wind River Formation.

55.4

Cliffs

58.5

Red cliffs on South and cliffs on North.

60.2

Cliffs North and South of the highway.

60.4

Cliffs North of the highway.

61.2

The Jurassic Nugget Formation

Wind River

The view from the highway of the floodplain of the Wind River shows the river’s well-developed meanders. Meanders are the loops that river channels make when gradients are low and the river carries mostly fine-grained sediments.

62.6

Cliffs

63.0

Cliffs

67.4

Cliffs

75.5

Downtown Dubois

0.0

Turn from North to West in Dubois.

7.6

This outcrop exposes a volcanic tuff. Tuff is the product of deposition of fragments of rock, frothy glass called pumice, and lava thrown from a volcanic vent in an explosive eruption. This explosively-erupted material is collectively called pyroclastics.

12.0

Oxbow in the making on the Wind River.

An oxbow lake, or just oxbow, is part of a river channel that has been abandoned. Oxbows are common along rivers whose channels meander across broad floodplains. During flood stage, a river may take a more direct path between two adjacent loops, cutting off a loop, which becomes an oxbow lake. Eventually, oxbows become filled in with sediment.

15.5

Wind River

17.7

Forest Service Rd 532; road to Lava Mountain.

19.8

Cliffs of the Pinnacles

23.7

The Pinnacles

25.5

Pinnacles

26.7

Forest Service road to Lava Mountain, pictures in Lander.

57.1

Moran Junction

0.0

Moran Junction; drive South.

6.3

"V" shaped valley between the Tetons.

14.8

Glacier turnout

18.3

Moose Junction; continue South.

23.9

Kelly Junction

37.0

Gros Ventre Slide East of Kelly.

The Gros Ventre Slide occurred in 1925 when a slab of Tensleep Sandstone, weakened and loaded by rain, broke loose and slid down the mountainside, damming the Gros Ventre River below. There were no casualties due to the slide itself, but two years later, on 18 May 1927, the rock dam was overtopped and collapsed. The wall of water that swept through the town of Kelly, four miles below, drowned 7 of the town’s 70 inhabitants.

50.1

Return to highway. Turn South.

57.8

Jackson Information Center

0.0

Jackson Information Center

19.8

Hoback Junction

25.2

New slide between Hoback and Alpine.

Beginning on 1 June 1997, about a million cubic yards of debris slid down the mountain side toward the Snake River. About 6000 cubic yards covered the road. Forestry experts studying the slide estimated that wood from the trees destroyed in the slide would have been enough to build several homes. More sliding is possible in this area in the future because of the steep slopes and unstable bedrock.

Trees bordering the slide have been twisted inward, including the root systems. The Snake River was forced to near flood stage by the slide and came close to covering the road. Highway engineers clearing the debris planned to push most of it into the river.

50.2

Return to Jackson Information Center

0.0

Information Center

190.4

Return to Lander

End of Loop 5