Horsetail Falls in Yosemite National Park ‘s firefall phenomenon. 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.\n\nEach 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.