Satellite images viewed in early 2009 indicate there has been a major landslide or debris flow dam on RIo Mezquital near Xoconoxtle that has backed up the river several kilometers. The slide appears just downstream of the Arroyo Hondo confluence in the last narrow gorges of the Xoconoxtle section (upstream of Puente Guamuchil). The water is backed up enough to suggest a ~50 m height. Downstream the riverbed appears severely scoured to a high level, suggesting either an initial huge debris flow (that may have created the dam) or a dam that was breached and resulted in a major flood. The riverbed is free of vegetation to a high level for over 50 km downstream, and the massive boulders in many rapids appear to have been rearranged.
If you go in there, take some pictures to compare with the photos I took in 2000, some of which you can see at
http://www.sierrarios.org/PagesGeneral/SlideshowLinks.html .
Rocky
