1.NounA summertime event held in Yosemite National Park from 1872 to 1968, in which burning hot embers were spilled from the top of Glacier Point to the valley below, giving the appearance of a glowing waterfall.
2.NounThe phenomenon whereby Horsetail Fall, a seasonal waterfall in Yosemite National Park, is illuminated by the sunset so that it glows orange-red.