Global Volcanism Program | Image GVP-06597
The Little Glass Mountain obsidian flow is seen here from Pumice Stone Mountain, named for the mantle of white pumice (foreground) from Little Glass Mountain that mantles the cone. The massive 0.4 cu km obsidian flow was erupted from a buried vent below Little Mt. Hoffman, which rises above the skyline at right center on the western rim of Medicine Lake caldera. The Little Glass Mountain pumice eruption and obsidian flow occurred about 1065 years ago during one of the youngest eruptions from Medicine Lake.
Photo by Lee Siebert, 1998 (Smithsonian Institution).