Yosemite has been forged by fire and ice. First came fire: magma, bubbling up from the interior of the earth, cooled to become granite, and rose to form the Sierra Nevada Mountains. Then came ice, rivers of ice: great glaciers flowed down out of the high country, to carve out incomparable Yosemite Valley.

In the latter half of February, when the low-angled light of the winter sun spins the frigid waters of Horsetail Fall into molten gold, the drama of fire and ice is reenacted for a few minutes at the end of each day.