Grand Falls, Arizona

April 23, 2010


Photographer: Joe Orman; Rick Scott
Summary Author: Joe Orman; Rick Scott

April 2010 Earth Science Picture of the Day Viewer's ChoiceTwo views of the splendid Grand Falls, Arizona are shown above. This turbid waterfall on the Little Colorado River in the high desert of northeastern Arizona is one of the state's best-kept secrets. The waters of the Little Colorado River become extremely muddy as they pass through the sandstone of the Colorado Plateau. At Grand Falls, the river is diverted from its original bed by an ancient lava flow dam, plunging 185 ft (56 m) over a wide escarpment. The Little Colorado eventually joins up with the Colorado River in the Grand Canyon, some 70 mi (113 km) downstream.
Grand Falls is higher than Niagara Falls but not as wide. On most days little water flows over the falls, and during dry periods discharge is reduced to a trickle and may even completely dry up. In late February 2010, the flow as measured by a stream gauge just above the falls was less than one cubic foot per second (cfs). However, by early April the flow rate surged dramatically due to runoff from rapid snowmelt in the White Mountains of eastern Arizona. A deeper than normal snowpack and a sudden warm spell in late March were responsible for the notable surge. On the day the top photo was taken, April 12, 2010, the discharge was measured at 1,100 cfs, resulting in spectacular cascades. The bottom photo was snapped ten days earlier. On rare occasion, the torrents at Grand Falls can be truly incredible. The highest flow ever recorded, on September 20, 1923, was an astounding 120,000 cfs.