has seven main vents, arranged in a line on the east bank of the Firehole River, not all visible from the path. Eruptions send water through all vents (which extend over 25 feet), to a height of 100 feet or more, and as some vents are angled left and right, the overall effect is a beautiful fan-shaped discharge, produced in conjunction with adjacent Mortar Geyser
, which always erupts at the same time. Some of the water falls directly on the path. Intervals between eruptions are irregular, varying from days to several weeks, but on some occasions there may be no activity for a year or more.
Back to map of the Upper Geyser Basin