FUMAROLE VALLEY

Fumarole Valley is a NW-trending valley on the southern flanks of the resurgent dome in the central caldera. There are several venting fumaroles at this site, but no surficial flow of thermal waters. The ground is very hydrothermally altered. Soil temperatures vary greatly with small distances. This is illustrated by the acceleration of the grass life cycle in some areas (where the grass is red and finally brown) which grades out into green grasses. The temperature of the ground where the grass is green is normal, while the temperatures under the red and brown grasses near 200F.

This image is taken looking west in early June of 1999.