ARCH_160716_423
Existing comment:
Pothole Arch Formation:
Pothole arches start as depressions near cliff face.

Pools of water collect the slowly deepen the pothole. Over time, water seeps through the cliff face, forming an alcove.

Eventually, the enlarging pothole meets the roof of the expanding alcove, creating an opening. The arch matures as erosion continues.
Proposed user comment: