At 185 feet tall (56 meters), it is taller than Niagara Falls. It dumps snow melt or monsoon rain into the Little Colorado River below. It is famous for its extremely muddy flow which is a major contributor to Little Colorado River opacity. It is said that the waterfalls are analogous to flowing chocolate depending on the amount of water present. Heavy rains or snow melt will produce spectacular viewing, photography and sound whereas the scarcity of water will produce only trickles or no flow at all.
Grand Falls was formed when lava from nearby Merriam Crater flowed into the Little Colorado River creating a lava dam. The river was forced to reroute itself around the dam and Grand falls formed where the reroute rejoins its original course.