Upper Mesa Falls is a waterfall on the Henrys Fork in the Caribou-Targhee National Forest. Upstream from Lower Mesa Falls, it is roughly 16 miles (26 km) away from Ashton, Idaho.[2]

Upper Mesa Falls
Upper Mesa Falls in June, 2008
Location	Fremont County, Idaho
Coordinates	44°11′16″N 111°19′48″W
Type	Block
Elevation	5,600 feet (1,707 m)
Total height	114 feet (35 m)[1]
Watercourse	Henrys Fork (Snake River)

Upper Mesa Falls is roughly 114 feet (35 m) high and 200 feet (61 m) wide.[3]

Formation

Mesa Falls Tuff, which is the rock over which Upper Mesa Falls cascades, was formed 1.3 million years ago. A cycle of rhyolitic volcanism from the Henrys Fork caldera deposited a thick layer of rock and ash across the area.[4] This layer compressed and hardened over time.

Between 200,000 and 600,000 years ago, the river eroded a wide canyon which was subsequently partly filled with basalt lava flows. The Henrys Fork of the Snake River then carved the channel through the basalt; which is the inner canyon seen today.

See also

• List of waterfalls in Idaho

References

Wikimedia Commons has media related to Upper Mesa Falls.

External links

• Mesa Falls Visitor Center (USDA Forest Service - Caribou-Targhee National Forest)

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