The Mogollon Rim — Arizona’s mighty backbone — has patterned both natural and human history. It gives the region both it’s history — rife with hardship and adventure — and it’s future, as an outdoor playground marked by private treasures on public lands.
The Mogollon Rim forms a wilderness rampart, topped by the historic Forest Road 300, a graveled route with a vivid history and a limitless supply of 100-mile views.
The deep gorges cut into this edge of the uplift that forms southern edge of the Colorado Plateau each expose walls of horizontally layered, sedimentary rocks that reveal a titanic contortion of the Earth.
Rocks that started out as layers of mud and ooze on the bottom of inland seas were first buried, then thrust upward thousands of feet due to shifts in gigantic crustal plates. Those same forces pushed up the Rocky Mountains.
The Colorado River then went to work on the southern edge of the uplift, creating the Grand Canyon. But along the eastern two-thirds of central Arizona, the rivers were less ambitious and so the uplift instead formed a massive line of cliffs sweeping from northwest to southwest into New Mexico.
Most of the streams couldn’t cut through the lip and so drain north. A few managed to chew through the rising layers of limestone and flow south.
From Pine to Young, the Rim’s buttressed face is rarely less than a near vertical drop of 2,000 feet. At many overlook points, the world drops away and views extend across a vast landscape.
South of Show Low the escarpment is again blanketed by com paratively recent volcanism. These volcanoes formed the core of the White Mountains from a once
molten layer of rock that covers much evidence of the plateau’s edge as one travels on into New Mexico.
Central Arizona is dependent upon the storm patterns created by that great barrier of stone. Storms brewed in the Pacific roar past the lower deserts, hit the wall of the Mogollon Rim and release their burden of moisture as they push over that barrier.
As a result, while Phoenix gets perhaps 8 inches of precipitation a year, Payson gets 22 — and the forests on top of the Rim get more than twice that amount.
The Rim divides the drainage in the state north to south. Much of the water drains off through the Salt, Gila and Verde rivers, providing water for Phoenix.
The rest drains to the north, down into the Little Colorado and on into the chain of reservoirs on the Colorado River. The top of the Rim flows into the Little Colorado, and all runoff below the backbone flows into the Verde, the Salt and the Gila rivers.