The Secrets of Yellowstone's West Thumb Geyser Basin
Most visitors to Yellowstone drive past the West Thumb Geyser Basin, busy heading to the Old Faithful Area. But if you have a couple of hours, park the car and explore this incredibly diverse area on the shores of the Yellowstone Lake. It offers spectacular lake views and colorful geothermal features.
The West Thumb Geyser Basin is located on the western shores of Yellowstone Lake, just north of Grand Teton National Park. The basin was formed approximately 150,000 years ago by a large volcanic explosion. The West Thumb caldera (volcanic crater) lies within a larger caldera, which encompasses the central and southern portions of Yellowstone National Park.
Thermal features at the West Thumb Geyser Basin include the Abyss Pool, Twin Geysers, Black Pool, Fishing Cone, Big Cone, Lakeshore Geyser, Lakeside Spring, Seismograph and Bluebell Pools and Thumb Paint Pots.
The pools of West Thumb feature bright colors such as green, brown, orange and yellow, created by heat-loving organisms that live in the pools. The best way to see the West Thumb Geyser Basin is to follow the ½-mile boardwalk loop which circles the Central Basin and its thermal features. There are two loops. The inner loop measures 1/4 mile while the outer loop, which passes near Yellowstone Lake, measures 1/2 mile. Even though the boardwalk does not have any steps, there is a steeper grade on the outer loop of the trail.
The trail leads visitors near colorful hot springs, lakeshore geysers and blue Yellowstone Lake. Observe how the thermal features extend under the surface of the lake. Underwater geysers can be seen as bulges on the lake’s surface. In the winter, hot water melts holes in the ice covering Yellowstone Lake. Read our Yellowstone vacation tips and The scenic drives of Yellowstone.
1. The Abyss and Black Pools at West Thumb
The Abyss Pool is 53 feet deep and is one of the deepest hot springs in the park. It was named in 1935 by Chief Park Naturalist C.M. Bauer. Abyss Pool has sloping walls that vary in color from turquoise blue to green and brown. Abyss Pool has gone through two active periods. It erupted in 1987 and several times in 1991/1992. Since that time, Abyss Pool has been quiet.
The Black Pool at the West Thumb Geyser Basin is one of the most beautiful pools in Yellowstone National Park. It is bright blue in color with steam rising from its hot surface. The Black Pool got its name when it was actually black. Until 1991 water temperature in this pool was lower so that Black Pool was inhabited by dark green and brown thermophiles, which gave the pool black appearance. Water temperature rose in 1991, followed by several eruptions, which made Black Pool too hot for thermophiles. Today, the Black Pool is quiet and a feature attraction at the West Thumb Geyser Basin.
2. The Big Cone and the Fishing Cone
The Big Cone peaks out of Yellowstone Lake and can be observed from the outer loop of the West Thumb Geyser Basin Trail. The Fishing Cone is a hot spring that got its name because men would fish in Yellowstone Lake and then boil their fish in the hot spring on the lakeshore. The Fishing Cone can be viewed from the outer loop of the West Thumb Geyser Basin Trail which passes next to Yellowstone Lake. Clearly, fishing is no longer allowed here in order to protect the hot spring from damage and ensure visitor safety.
3. The Lakeshore Geyser and Spring
The Lakeshore Geyser boils vigorously and almost continuously. The geyser frequently erupts, but only a few feet. Lakeshore Geyser is located next to Yellowstone Lake. To view the geyser, visitors should follow the outer loop of the West Thumb Geyser Basin Trail which passes next to the geyser and Yellowstone Lake.
The Lakeside Spring features a palette of colors, ranging from blue to brown. A blue-green pool of thermal water runs off in a brown-yellow spring. Heat-loving microorganisms provide color to thermal features in Yellowstone.
4. Seismograph and Bluebell Pools
The two pools are blue in color. The Seismograph pool occasionally collects mud from nearby mudpots. Seismograph and Bluebell Pools can be viewed from the outer loop of the West Thumb Geyser Basin Trail. A steep grade connects the outer loop boardwalk with the inner loop. The two pools are located next to that grade.
5. Thumb Paint Pots and Central Basin
The Thumb Paint Pots are located in the Central Basin. Mudpots differ from hot springs in that their water is much more acidic and dissolves the underground into clay mud. Thumb Paint Pots are constantly changing, passing through periods of activity and inactivity.
The Central Basin at West Thumb is one of the most dynamic areas in Yellowstone National Park. Surging Spring overflows frequently and sends hot water down towards Yellowstone Lake. The Ledge Spring and Collapsing Pool fluctuate from overflowing to half empty. The best way to see the Central Basin is to walk the West Thumb Geyser Basin Trail, which circles the basin. Visitors can admire colorful pools created by thermal waters and heat-loving microorganisms which inhabit them. In addition to exciting thermal activity this area offers beautiful views of the Yellowstone Lake.
6. Yellowstone Lake
The Yellowstone Lake is the largest lake in Yellowstone National Park. It covers 136 square miles and is 20 miles long by 14 miles wide. For some of the best views of Yellowstone Lake, visit West Thumb Geyser Basin at sunset. There will be very few visitors at that time and you will be able to enjoy spectacular views of the lake surrounded by geysers and colorful thermal pools. In the summer, look for bald eagles and osprey along the lake shore.
Xanterra Parks & Resorts offers guided fishing and boat rentals at Bridge Bay Marina on Yellowstone Lake. Call 307-344-7311 for more information. The lake features 110 miles of shoreline, but it remains too cold for swimming year-round. The lake completely freezes over in the winter. The Yellowstone Lake is home to the largest population of wild cutthroat trout in North America. Several species, including the cutthroat trout, are subject to catch-and-release-only fishing rules in the park.
From the West Thumb Geyser Basin, the drive to the Old Faithful takes anywhere from 30 minutes to one hour in the summer, depending on the traffic and road repair work. There are a few picnic areas and scenic turnouts from which visitors can admire the park landscape. The road from West Thumb to Old Faithful crosses the Continental Divide two times: at 8,391 feet and at 8,262 feet. One the way, you can admire views of rivers, forests, lakes and waterfalls.