The Future
What will Zion National Park be like in the future? Nobody knows for certain, but one can assume to the best of their knowledge.
The first major difference that we will most likely see in the future is the depth of the canyons in Zion National park. The rivers in the park, such as the Virgin River, are not even close to reaching their ultimate base level. They all have many layers of resistant that they need to erode through to reach that ultimate level. Therefore, the steeper gradient levels that the land has achieved right now will continue to make the rivers in the park flow faster and downcut the rock at high speeds. The canyons of Zion National Park will get deeper!
The second major change that will most likely occur is a widening of the canyon and a change in wall steepness so that the canyon walls are less steep and not practically vertical. At this moment in time, present day, the canyon walls throughout Zion National Park are very steep. Such steep walls make mechanical weathering techniques faster and more effective. For example, when frost wedging occurs, the piece of rock must be wedged far enough so that it will fall down the slop. With an almost vertical slope present, it does not take as much wedging to get the piece of rock to fall. In addition to expedited mechanical weathering processes, the steep slopes also make mass wasting a probable future process. When the rock in the walls of the canyon become less stable, the angle of repose for the walls will lower and the slope will most likely give way to a rockslide or other form of mass wasting. The final reason that I have to back-up this claim of the canyon widening and the walls becoming less steep is a real life example. The Grand Canyon, a well known canyon in the same area as the Zion Canyons, is very wide and has less steep walls. The Grand Canyon is also Much older than the Zion Canyons, therefore it can act as proof that, someday, the younger canyons in Zion National Park will widen and their walls will become less steep.