Erosional remnant showing effects of differential weathering and erosion, Monument Valley, AZ. Cliff-forming rock is Permian De Chelly Sandstone (eolian); slope-former is Permian Organ Rock Shale. (090321-55f)
Grus, small angular fragments of granitic material formed by chemical (hydrolysis) and mechanical weathering of granitic rock, Montana. Slope of deposit approximates the angle of repose for this material. (170528-3)
In 2004, a flash flood swept down Furnace Creek Wash in Death Valley National Park, tearing up the state highway and destroying the structures in and around the Zabriskie Point area. Such flash floods are relatively common, as most rainfall tends to run off into channels instead of soak into the ground. This particular flood was especially severe though because the rain fell in small area over a short amount of time.