Yosemite's "Horsetail Fall" Evokes Lava Flow Image Credit: Scott Gediman of the Yosemite National Park Service/AP A breathtaking natural phenomenon that only happens once a year is drawing throngs of tourists, sightseers and photographers alike to California's Yosemite National Park. Their eyes and camera lenses are pointed toward Horsetail Fall, a little-known waterfall on the east end of El Capitan in the famed national park that becomes a star a few days each February when the sun and earth align just so. PHOTOS: Volcano Viewing Around the World When they do, the setting sun illuminates the ribbon of water flowing from the granite face of El Capitan so that it resembles a waterfall on fire, much like flowing lava. The sight to behold only lasts for about two minutes, only occurs for about two weeks in mid-February and only if the winter weather cooperates. The southwestern horizon must be clear in order to see it and the right amount of water must be flowing into the fall. The sight is a good one this year thanks to recent snowfall that is now melting and feeding the water stream that flows into Horsetail, according to park officials. The Horsetail spectacle was first recorded in color in 1973 by the late renowned outdoors photographer Galen Rowell, the Associated Press reports. Park officials say the good conditions this year make them hopeful the spectacle will last through February 24, generally the last day of the year it can be seen.