during a couple of weeks throughout February, Yosemite's waterfall seems to be blazed by the setting sun. It's a fantastic observation that's rare. The effect is finicky, requiring superb conditions. For example, the unset must catch the 1,000-foot-tall horsetail fall just right to illuminate the mist with reds and oranges. If it all goes well the Yosemite Valley's rocky peaks progressively coat El Capitan in shadow from west to east during sunset, leaving a narrow swath of light on the waterfall just before sundown. This makes seem as if there was lava inside the fall.
http://news.nationalgeographic.com/2016/02/160219-yosemite-firefall-waterfall-sunset-pictures-nature/
http://news.nationalgeographic.com/2016/02/160219-yosemite-firefall-waterfall-sunset-pictures-nature/