Conor Watkins And J. David Rogers
Grand Canyon Research
Rockfalls, Landsliding And Channel Diversion At Blacktail Canyon

Blacktail Canyon (RM 120) is among the many scenic side canyons in Grand Canyon.  It is noted for its narrow slot and picturesque waterfalls in the Tapeats Sandstone.  Most visitors do not venture beyond the first waterfall in the canyon.  Several landslides and rockfalls in the Bright Angel and Muav Formations are exposed in upper Blacktail Canyon, a portion that must be accessed via a technical climb or by hiking around the slot on its west side.  The canyon widens dramatically once it enters these weaker formations.

During March-April 2005 we conducted a reconnaissance of Blacktail Canyon (RM 120) while participating in a Grand Canyon River Guides training trip.  During the investigation, evidence of multiple landslide dams and a recently formed rockfall dam were discovered.

Blacktail Canyon (RM 120) appears as a slot canyon in the Tapeats Sandstone when viewed at river level.

Upper Blacktail Canyon is littered with brecciated slide debris.  These landslides appear quite old and are highly eroded.

The above picture shows a recent rockfall that has dammed Blacktail Canyon as viewed from downstream (note person for scale).  For now, the course debris is allowing the intermittent flow of Blacktail Canyon to run through the blockage and the dam has not breached.

Notice the ponding of fine-grained sediments behind the rockfall dam.  This occurs when the flowing water in Blacktail Canyon is temporarily ponded behind the rockfall dam, allowing sediments to be deposited.  The sediments will likely one day plug the voids within the debris, allowing it to retain water.  Once this happens, the dam will likely overtop and breach.


Several landslide dams have blocked Blacktail Canyon, forcing it to divert around the blockages.  The above pictures show an excellent exposure of a buried channel within Blacktail Canyon on its east side.  These pictures were taken at the downstream end of the exposed channel fill.

Questions or comments on this page?
E-mail Dr. J David Rogers at
or Conor Watkins at