I took this photo during a visit to Bryce Canyon National Park. What special erosional conditions formed these amazing rock structures?
The strange "hoodoos" of Bryce Canyon are caused by very special conditions. The rocks are soft, so they erode fairly easily. If rain from the highlands above drained into them, they would have eroded away quickly. Instead, the slope of the highlands is away from Bryce Canyon, so the only water that erodes them is the rain that falls directly on the rocks. This causes the canyons to grow deeper instead of wider, producing the spectacular hoodoos.