File:Yosemite National Park - Fire Falls - Flickr - RuggyBearLA.jpg

Horsetail Fall flows over the eastern edge of El Capitan in Yosemite Valley. This small waterfall usually flows only during winter and is easy to miss. On rare occasions during mid- to late February, it can glow orange when it's backlit by sunset. This unique lighting effect happens only on evenings with a clear sky when the waterfall is flowing. Even some haze or minor cloudiness can greatly diminish or eliminate the effect. Although entirely natural, the phenomenon is reminiscent of the human-caused Firefall that historically occurred from Glacier Point.

Yosemite National Park is an American national park in the western Sierra Nevada of Central California, bounded on the southeast by Sierra National Forest and on the northwest by Stanislaus National Forest. The park is managed by the National Park Service and covers an area of 748,436 acres (1,169 sq mi; 3,029 km2) and sits in four counties: centered in Tuolumne and Mariposa, extending north and east to Mono and south to Madera County. Designated a World Heritage Site in 1984, Yosemite is internationally recognized for its granite cliffs, waterfalls, clear streams, giant sequoia groves, lakes, mountains, meadows, glaciers, and biological diversity. Almost 95% of the park is designated wilderness.

On average, about four million people visit Yosemite each year, and most spend the majority of their time in the seven square miles (18 km2) of Yosemite Valley. The park set a visitation record in 2016, surpassing five million visitors for the first time in its history. Yosemite was central to the development of the national park idea. Galen Clark and others lobbied to protect Yosemite Valley from development, ultimately leading to President Abraham Lincoln's signing the Yosemite Grant in 1864. John Muir led a successful movement to have Congress establish a larger national park by 1890, one which encompassed the valley and its surrounding mountains and forests, paving the way for the National Park System.

Sources: www.nps.gov/yose/planyourvisit/horsetailfall.htm