Upper Mesa Falls | |
Photo Width: | 200 |
Location: | Fremont County, Idaho |
Coords: | 44.1878°N -111.33°W |
Elevation: | 5600feet |
Type: | Block |
Height: | 114feet[1] |
Watercourse: | Henrys Fork (Snake River) |
Upper Mesa Falls is a waterfall on the Henrys Fork in the Caribou-Targhee National Forest. Upstream from Lower Mesa Falls, it is roughly 16miles away from Ashton, Idaho.
Upper Mesa Falls is roughly 114feet high and 200feet wide.[2]
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.[3] 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.