Overflow from Sawmill Geyser runs down a sinter-lined channel to the Firehole River. Cooling rapidly in the February night, the water had steamed and grown these feathery crystals on the margins of the sinter channel. The runoff channel is an old one, and orange lichen has grown on the rocks, too. The long crystals grew down, each hanging from a tiny point on the rock’s edge. Fluttering occasionally in the faint breeze they accumulated moisture until they became too heavy and the breeze became too strong and broke them off and blew them away.