Mile 135-136 - Granite Narrows
Igneous and metamorphic rock has been exposed here, creating a narrow slot for the river to run through. At one spot in these narrows, the river is less than 100 feet from shoreline to shoreline. During the most recent high water episodes in Grand Canyon, one just before dam construction in 1957 and the other during the post-dam period in 1983, the river became squeezed so tightly through the narrows that it slammed with great force into the cliffs. The cliffs deflected the river’s current at near right angles, causing swirls and boils that overturned several crafts.