Horsetail Fall is a seasonal waterfall in Yosemite National Park in California. In February if Horsetail Fall is flowing and the weather conditions are just right, the setting sun illuminates the waterfall, making it glow orange and red. 

 

This natural phenomenon is often referred to as the "Firefall", a name that pays homage to Yosemite Firefall, the man-made event that once took place in Yosemite.