The origins of the thousands of small canyons found in the area may be puzzling at first glance. Most of the year, time seems to stand still and the process of erosion is imperceptible. To witness the occasional rock fall or landslide is exceptional luck. But, some of the erosive processes are sudden and violent. Sparse vegetation and an abundance of exposed rock make Canyonlands especially vulnerable to flash flooding.
Thunderstorms drop huge amounts of rain locally.
With little soil and vegetation to hold the water, runoff is fast. It quickly collects in gullies and small washes, magnifying its power as water funnels into the canyons. The erosive power of the debris and sediment -laden water is tremendous. Flash floods are continually scouring and deepening the canyons. Needles and Spires Three hundred million years ago this area was a great low-lying basin partially open to the sea.