From Waterfall to LavaFall: Yosemite's Fleeting Phenomenon
"If you head to Yosemite National Park this time of year and stop by Horsetail Fall at just the right time, you 
might see something spectacular: As the sun sinks low in the sky, the waterfall glows with streaks of gold and yellow — and it looks just like molten lava."
"Photographers like Michael Frye flock to the park every February to try to capture the phenomenon. Frye, author of The Photographer's Guide to Yosemite, describes the sight to NPR's Audie Cornish."