These photos were taken by Aaron Flesch before and after the February 2 and 3, 2011 frost. This unusually severe frost event was the worst freeze seen across Sonora and Arizona at least 50 years. Many species and vegetation communities were heavily effected.
These photos were taken in July 2009 (top) and July 2012 (bottom). One can see dramatic changes in vegetative cover in the foreground, as well as on hill-slopes in the background.