Illuminated by the setting sun on Yosemite"s famous El Capitan is a rare natural phenomenon known as the "Firefall," which appears for just a few weeks a year. From mid to late February, the sun is at just the right angle to set Horsetail Fall aglow, but only if sufficient water is flowing and the sky is clear. Even then, the Firefall only lasts for about 10 minutes in the evening, so vantage points can be very crowded.