One thing the Colorado Plateau is famous for is the abundance of slot canyons. These are usually very narrow canyons either with or without a running stream. In the case of the Zion Narrows of the Virgin River, the canyon closes in to about twenty feet wide in some places, with the rapidly flowing and very cold water of the Virgin River. The walls of the canyon can be hundreds, if not thousands of feet on each side. Hiking into these canyons is challenge and should never be lightly undertaken. Regularly, people are killed by encountering flash floods while attempting to navigate these narrow canyons.