GOSA (The Geyser Observation and Study Association) West Thumb Geyser Basin  

West Thumb Geyser Basin:

West Thumb Geyser Basin consists of a narrow strip of geysers, hotsprings and a few mud pots located on the west shore of the "West Thumb" portion of Yellowstone Lake. The lake setting makes this a very beautiful area.

Lone Pine Geyser

Lone Pine Geyser: [Picture]

Lone Pine Geyser is is currently the largest frequent geyser at West Thumb Geyser Basin. It is located a few hundred yard north of the main boardwalk portion of the basin. Between the road and Yellowstone Lake. Its picturesque appearance and unexpected location along the lake often leads to traffic jams during its eruptions.

Lone Pine is a cone-type geyser. Eruptions can reach 75 feet in height. Currently (late 1999) it is quite predictable, with intervals usually between 16-17 hours but sometimes ranging from 15-19 hours. Durations are about twenty minutes. Major eruptions start from a full pool. There is little warning before the eruption. Only slight bubbling and convection currents can be seen over the vent. A few minutes before the eruption, the boiling increases and then the eruption starts. Minor eruptions can occur an hour or two after the major eruption. These eruptions start from an apparently empty crater and last about five minutes. The pool refills and begins quietly overflowing 4-5 hours after the major eruption. The occurrence of minors does not seem to affect the refill rate significantly. Once full, the pool overflows quietly until the next eruption.

Big Cone: [Picture]

Big Cone is a large sinter cone that sticks out of Yellowstone Lake near Fishing Cone.

Blue Funnel Spring:

[The description of Blue Funnel was provided by Steve Gryc.]

Although there has been occasional and dramatic geyser activity at West Thumb, eruptions are rare occurrences.  There are, however, a large number of beautifully-colored hot pools in West Thumb's central basin, making any visit to this unique area a rewarding one.  Blue Funnel Spring is one of the larger pools and one of the most striking because of its circular rim and pastel blue color which intensifies as the pool deepens towards its central vent. The hottest pools are the bluest since colorful cyanobacteria that live in cooler springs change the color of those springs.

Blue Funnel Spring is located about 280 feet southeast of Twin Geyer.

Hillside Geyser: [Picture]

Hillside Geyser is an infrequent player at West Thumb. The 45 foot tall cone-type geyser has only been seen a handful of times in the late nineties. The last eruptions occurring decades ago. The geyser erupts with very little warning. Suddenly boiling up and quickly erupting. Most of the time, it is a little noticed hole about halfway between Black Pool and Twin Geyser. Durations are 4-5 minutes.

Lakeshore Geyser: [Picture]

Lakeshore Geyser is located on the edge of Yellowstone Lake. In fact, most of the time it is inundated by cold lake water. Rendering the geyser dormant. It can only erupt on those rare occasions when both the lake is low and the geyser is hot. This is a fairly rare occurrence.

There have been periods of time though, when Lakeshore has been quite active. During periods in the late 1800's and early 1900's for instance. When active, the cone-type geyser can reach 25-30 feet. During the 1990's activity was noted in 1992 and 1993 when small one foot eruptions were seen. Activity of some sort may have also occurred in 1998 based on a larger area of sinter patina than could be accounted for by the boils seen.

Seismograph Pool: [Picture]

Seismograph Pool was probably named for changes incurred after the 1959 earthquake but no one is sure.

Thumb Paint Pots: [Picture]

The Thumb Paint Pots were much more active during the early history of the park. Now, they do little more than bloop a little. In fact much of the time, they are no more than very soupy muddy water.

Twin Geyser: [Picture]

Twin Geyser is a major geyser, erupting 75-100+ feet high. It erupts from two vents closely spaced. The eruption starts from the north vent and just as it appears the eruption is about to stop, the south vent takes over and the eruption again builds to full strength. The eruption lasts 3-4