The natural Firefall is one of Yosemite’s most amazing...

[The Librarian]

The natural Firefall is one of Yosemite’s most amazing spectacles. Around the second week of February, the setting sun hits Horsetail Fall at just the right angle to illuminate the upper reaches of the waterfall. And when conditions are perfect, Horsetail Fall glows orange and red at sunset.

Each year in late February, hundreds of spectators gather in Yosemite to witness this amazing event. But If conditions are not perfect, the Yosemite Firefall will not glow. First and foremost, Horsetail Fall must be flowing. If there’s not enough snowpack in February, there will not be enough snowmelt to feed the waterfall, which tumbles 1,570 feet (480 meters) down the east face of El Capitan. Likewise, temperatures must be warm enough during the day to melt the snowpack. If temperatures are too cold, the snow will stay frozen and Horsetail Fall won’t flow. (Lack of runoff is also why there is no Firefall in autumn. Although the sun hits Yosemite Valley at the same angle in October as it does in February, Horsetail Falls is usually dry in October because the runoff that feeds it has long since dried up.) Second, the western sky must be clear at sunset. If it’s snowing, raining, or even just cloudy, the sun’s rays will be blocked and Horsetail Falls will not light up. Winter weather can be highly variable in Yosemite, however, and days that start off cloudy can clear up by sunset. If everything comes together and conditions are just right, the Yosemite Firefall will light up for about ten minutes. To see Horsetail Fall glowing blood red is an almost supernatural experience.

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