I've hiked the Grand Canyon four times now, and the first three times were disappointing because of the lack of clouds. That is, the GC begs for clouds both to dress up the sky, and to lend additional shadow interest to the canyon features. Otherwise, except for the very early morning and late afternoon, the canyon appears dull and flat (especially with the incessant pollution that now exists within it's otherwise beautiful confines). My most recent trip, a brief side trip from a journey to points further west for the holidays, started out once again bleak: Forecast for 50% coverage clouds at 6 a.m. and there were virtually none. However, as the day wore on and I tramped around the rim some cloud coverage did move in. In fact, it became quite heavily overcast. It turned out to be worth the trip this time because I was able to capture the image you see above--my last of the day. This image was shot from Lipan Point in December 2011. A Canon 7D was used with a wide-open 10-22 mm Canon lens. A +2 graduated neutral density filter was used to control sky brightness.