RRFW Riverwire – Hance Rapid Undergoes Major Change
August 25, 2012
On the Colorado River in Grand Canyon, Hance Rapid at River Mile 77.2, is one of the handful of difficult and legendary rapids where the run is rocky and the holes many. The rapid is a thirty foot drop in a little over a half mile, as measured in the 1923 USGS survey.
A series of monsoon storms in the last two weeks have brought massive amounts of boulders and gravel to the rapid via Red Canyon, the side canyon responsible for the debris in the river at Hance Rapid.
The left run of Hance is often chosen by river runners to avoid large right side holes. Due to recent flooding, the left run is now blocked by boulders and gravel. The new material has moved more of the river’s flow to the center of the river. Scouting the rapid in its new configuration is strongly advised.
The distinctive large room sized boulder on river left, known variously as the Muffin or Brain or Hamburger rock, was the marker for the left run. River runners attempting this route would try entering to the left of this boulder to enter the slower water just below it.
Before the construction of Glen Canyon Dam, completed in 1963, spring snowmelt river flows well over 100,000 cubic feet per second would clear away boulders and gravel from side canyon flood events like the one in Red Canyon. Today, managed flood flows only reach 45,000 cubic feet per second, too low to flush the side canyon debris on down the Colorado River, potentially making rapids much more difficult, especially at low water
Two aerial photos of the new rapid taken August 24, 2012, have been posted at the River Runners for Wilderness photo Gallery. RRFW would like to thank Michael McComb for the use of these photos. The link to the photos is here:
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