Chapter 9-4: Lake Powell Part II
May 12, 2021
As we walked up the pebbly floor of the narrow canyon, we came across an enormous boulder lodged between the nearly vertical walls of the canyon. The boulder with its speckled white and black color was not a sedimentary rock. The visible quartz, feldspar, biotite crystals indicated it was part of the igneous intrusion that created the Henry Mountains over 21 million years ago. This boulder, almost the size of a small Mini-Cooper had been carried down from the mountains, eight miles away simply by the action of fast flowing water. These canyons can be death traps when summer storms dump up to six inches of rain in two hours. It was a grim reminder of the power of fast flowing water and that this slot canyon was not a place to be hiking if a thunderstorm was centered over the nearby Henry Mountains.
Henry Mountains, Utah
Antelope Canyon, on the western end of Lake Powell with its meandering walls of sandstone, is a much-photographed slot canyon. In the summer of 1997, two groups of sightseers, 12 people in all, were on the sandy floor of the canyon. As they took pictures and soaked up the scenery, a summer storm dumped rain on the desert miles upstream. As that water drained toward Lake Powell, it picked up rocks and debris. By the time it reached the twisting canyon, it was a head-high wall of debris, racing toward the tourists. Only one person survived, the rest were swept away and drowned.