The natural Firefall is one of Yosemite National Park’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 the Yosemite Firefall can be finicky. Although Horsetail Fall is visible from multiple viewpoints in Yosemite Valley, several factors must converge to trigger the Firefall. 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 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.
The discovery of the natural Yosemite Firefall is not well documented. The Awahneechee Indians, who lived in Yosemite Valley for hundreds of years, most likely knew of its existence, but there is no evidence they passed this information on to white settlers. Yosemite Valley was discovered by white explorers in 1851, and although its natural wonders were heavily promoted afterwards, the natural Firefall was never mentioned. Even John Muir, who lived in Yosemite for several years and explored the park in obsessive detail, never mentioned the Firefall at Horsetail Fall.
In 1973 the photographer Galen Rowell took the first-known photograph of the natural Yosemite Firefall, which greatly increased its fame among landscape photographers and Yosemite aficionados. But it wasn’t until the digital photography revolution and the rise of internet that the Firefall achieved global fame. As chain emails, photography blogs, and photo-sharing sites flourished in the first decade of the 21st century, dramatic images of the Firefall spread around the world. These days hundreds of photographers and spectators visit Yosemite Valley each February, hoping to catch a rare glimpse of this amazing natural phenomenon.