The formation of hoodoos, which are tall, thin spires of rock, is primarily the result of a combination of weathering and erosion processes. Specifically, differential erosion plays a key role in their development.
Hoodoos typically form in sedimentary rock layers, where harder rock layers cap softer rock layers beneath. Over time, the softer rock erodes more quickly due to weathering processes such as water infiltration, freeze-thaw cycles, and chemical weathering. This differential erosion leads to the distinctive column-like formations of hoodoos, with the harder rock on top protecting the softer rock below from eroding as quickly.
The combination of these geological and erosional processes creates the striking and irregular shapes characteristic of hoodoos, often seen in arid and semi-arid regions, such as those found in places like Bryce Canyon National Park in Utah.