Horsetail Fall is a seasonal waterfall in Yosemite National Park that flows in winter and early spring. For a few evenings in February, the setting sun causes the waterfall to glow orange and appear as if it is on fire, hence its name "Fire Fall." The sunlight reflects off the falling water at just the right angle to create a spectacular but brief illusion of a flowing cascade of liquid fire. People gather each year, waiting for the perfect conditions to witness this natural light show.