The first all photographic field guide to Yellowstone's geysers, hot springs and fumaroles.

Yellowstone's geysers, hot springs, and fumaroles are unique and fragile features. Weak and thin sinter crusts and ledges surround many of these thermal springs. By leaving the boardwalk these features are easily damaged and severe injuries can result when fragile crusts give way into boiling water. For the protection of Yellowstone's thermal basins and your safety, please remain on the boardwalks and designated trails.

128pp.