As the drilling of potholes evolves during repeated flooding events or stronger floods of longer duration, the vortices can change directions and spiral and this creates the many beautiful patterns seen in more advanced pothole erosion. More erosion will also occur - so the original potholes can be more difficult to discern as they are eroded away.
Snip from http://en.wikipedia.org/wiki/Vortex : …Once formed, vortices can move, stretch, twist, and interact in complex ways. A moving vortex carries with it some angular and linear momentum, energy, and mass. In a stationary vortex, the streamlines and pathlines are closed. In a moving or evolving vortex the streamlines and pathlines are usually spirals….
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From left to right: Basalt Arch, Telford-Crab Creek Tract, Washington Scablands. A wall of basalt between two potholes was undermined by turbulent flood water vortices and only the top of the wall remains, forming an arch; Looking up inside Upper Antelope Canyon Utah - NASA photo
From left to right: Advanced pothole topography at Kruger National Park, South Africa – the remnant, partial, rounded walls of several deep potholes are still evident; Blyde River Canyon, South Africa – advanced potholes that have merged and created arches and multiple levels; Mostnica Gorge – Slovenia – an advanced pothole topography with an arch
Slot Canyons Examples
Slot Canyons display many beautiful examples of advanced pothole topography. This includes tunneling and intricate spiral shapes as well as larger vertical potholes and deeper horizontal plucking.
From left to right: Peek-a-boo Slot Canyon shows advanced patterns of tunneling from flood waters; Emerald pool at Subway, Zion National Park, Utah; Antelope Canyon, Arizona, USA - beautiful monument of floodwater carving - full of remnants of potholes that have merged together and enlarged the opening of the once narrow canyon – it is still a narrow slot at the top
From left to right: Antelope Canyon, a deep narrow slot canyon formed by water and wind erosion. Navajo Tribal Lands. Strong vortices of water carrying rock debris carved out what looks like a giant pothole here; golden reflection
© Laura Fitzpatrick 2014