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  • Writer's pictureDeborah Kade

Yellowstone Lake - West Thumb Geyser Basin - Mud Volcano

Updated: Oct 14, 2019

May 14, 2019

Today's drive took us to Grant Village and West Thumb Geyser Basin which are along Yellowstone Lake. Also, continued the drive up to Mud Volcano. So much more snow as compared to the area around Old Faithful and Mammoth Hot Springs. The temperatures were cooler, too.

Yellowstone Lake is the largest body of water in Yellowstone National Park. The lake is 7,732 feet (2,357 m) above sea level and covers 136 square miles (350 km2) with 110 miles (180 km) of shoreline. While the average depth of the lake is 139 ft (42 m), its greatest depth is at least 394 ft (120 m). Yellowstone Lake is the largest freshwater lake above 7,000 ft (2,100 m) in North America.

In winter, ice nearly 3 ft (0.91 m) thick covers much of the lake except where shallow water covers hot springs. The lake freezes over by early December and can remain frozen until late May or early June.

In winter, holes in the thick ice indicate hot spots in the lake bed where thermal features bubble up. Otters often fish in those melt holes.

The forest and valleys surrounding Yellowstone Lake had been populated with Native Americans since prehistoric times. The first human of European descent to see the lake was trapper John Colter in the early 19th century. During the fur trading era of 1820-1840, the lake was probably visited by many trapping parties moving through the park region.

The lake has been known by various names as depicted on early maps and in journals. Both fur trader David Thompson and explorer William Clark referred to the lake as Yellow Stone. Osborne Russell referred to the lake as Yellow Stone Lake in his 1834 journal. On some William Clark maps, the lake has the name Eustis Lake and the name Sublette's Lake was also used to name the lake in the early 19th century. The name Yellowstone Lake appears formally first in the 1839 maps of the Oregon Territory by U.S. Army topographical engineer, Captain Washington Hood and has remained so since that time.

In the southwest area of the lake, the West Thumb geothermal area is easily accessible to visitors. Geysers, fumeroles and hot springs are found both alongside and in the lake.

As of 2004, the ground under the lake has started to rise significantly, indicating increased geological activity, and limited areas of the national park have been closed to the public. As of 2005, no areas are currently off limits aside from those normally allowing limited access such as around the West Thumb Geyser Basin. There is a 'bulge' about 2,000 ft (610 m) long and 100 ft (30 m) high under a section of Yellowstone Lake, where there are a variety of faults, hot springs and small craters.

Seismic imaging has recently shown that sediment layers are tilted, but how old this feature is has not yet been established.

After the magma chamber under the Yellowstone area collapsed 640,000 years ago in its previous great eruption, it formed a large caldera that was later partially filled by subsequent lava flows. Part of this caldera is the 136 sq mi (350 km2) basin of Yellowstone Lake. The original lake was 200 ft (61 m) higher than the present-day lake, extending northward across Hayden Valley to the base of Mount Washburn.

It is thought that Yellowstone Lake originally drained south into the Pacific Ocean via the Snake River. The lake currently drains north from its only outlet, the Yellowstone River, at Fishing Bridge. The elevation of the lake's north end does not drop substantially until LeHardy Rapids. Therefore, this spot is considered the actual northern boundary of Yellowstone Lake. Within a short distance downstream the Yellowstone River plunges first over the upper and then the lower falls and races north through the Grand Canyon of the Yellowstone.

In the 1990s, geological research determined that the two volcanic vents, now known as "resurgent domes ", are rising again. From year to year, they either rise or fall, with an average net uplift of about one inch per year. During the period between 1923 and 1985, the Sour Creek Dome was rising. In the years since 1986, it has either declined or remained the same. The resurgence of the Sour Creek dome, just north of Fishing Bridge is causing Yellowstone Lake to "tilt" southward. Larger sandy beaches can now be found on the north shore of the lake, and flooded areas can be found in the southern arms.

The Hayden Valley was once filled by an arm of Yellowstone Lake. As a result, it contains fine-grained lake sediments that are now covered with glacial till left from the most recent glacial retreat 13,000 years ago. Because the glacial till contains many different grain sizes, including clay and a thin layer of lake sediments, water cannot percolate readily into the ground. This is why the Hayden Valley is marshy and has little encroachment of trees.

While many of the park's features had been described by mountain men and other explorers, the West Thumb area was the first Yellowstone feature to be written about in a publication. Daniel T. Potts, a trapper in the Yellowstone region in the 1820s, wrote a letter to his brother in Philadelphia, Pennsylvania, regarding his experiences in this area.

The letter was later corrected for punctuation and spelling and printed in the Philadelphia Gazette on September 27, 1827. Part of the letter describing the northern part of the West Thumb Geyser Basin, which is currently known as "Potts Basin" follows:

"...on the south borders of this lake is a number of hot and boiling springs some of water and others of most beautiful fine clay and resembles that of a mush pot and throws its particles to the immense height of from twenty to thirty feet in height. The clay is white and of a pink and water appears fathomless as it appears to be entirely hollow underneath. There is also a number of places where the pure sulfur is sent forth in abundance. One of our men visited one of those whilst taking his recreation. There at an instant the earth began a tremendous trembling and he with difficulty made his escape when an explosion took place resembling that of thunder. During our stay in that quarter, I heard it every day."

In 1869, the first scientific expedition to explore the Yellowstone area, the Folsom- Cook-Peterson Expedition, visited the West Thumb Geyser Basin. David Folsom described the area as follows:

"Among these were springs differing from any we had previously seen. They were situated along the shore for a distance of two miles, extending back from it about five hundred yards and into the lake perhaps as many feet. There were several hundred springs here, varying in size from miniature fountains to pools or wells seventy-five feet in diameter and of great depth. The water had a pale violet tinge, and was very clear, enabling us to discern small objects fifty or sixty feet below the surface. A small cluster of mud springs near by claimed our attention. These were filled with mud, resembling thick paint of the finest quality, differing in color from pure white to the various shades of yellow, pink, red and violet. During the afternoon they threw mud to the height of fifteen feet. . . ."

Historically, visitors traveling to Yellowstone would arrive at West Thumb via stagecoach from the Old Faithful area. At West Thumb, they had the choice of continuing on the dusty, bumpy stagecoach or boarding the steamship "Zillah" to continue the journey to the Lake Hotel. The boat dock was located near the south end of the basin near Lakeside Spring.

The West Thumb area used to be the site of a large campground, cabins, a photo shop, a cafeteria, and a gas station. This development was located immediately next to the geyser basin with the park road passing between the two. In an effort to further protect the scenic quality and the very resource that visitors were coming to see, the National Park Service removed this development in the 1980s.

Surprised to see so many wild flowers growing in this area.

West Thumb's shoreline has suspiciously crater like contours. Its underwater profile is dramatically deeper than the rest of Yellowstone Lake. Only a massive explosion could have formed West Thumb.

Though the blowout occurred 125,000 years ago, West Thumb is still thermally active. Hot springs, mudpots, and geysers stream and percolate along the shore, and temperature gauges record high heat flow in lake bottom sediments.

Bluebell Pool

Thumb Paint Pots

Lakeside Spring

Lakeshore Geyser

Fishing Cone is a hot spring.

The Folsom party probably saw it in 1869, but the first recorded description of Fishing Cone comes from the 1870 Washburn Expedition. Party member Walter Trumball wrote about Cornelius Hedges's experience fishing:

"A gentleman was fishing from one of the narrow isthmuses or shelves of rock, which divided one of these hot springs from the Yellowstone Lake, when, in swinging a trout ashore, it accidentally got off the hook and fell into the spring. For a moment it darted about with wonderful rapidity, as if seeking an outlet. Then it came to the top, dead, and literally boiled."

From that time on, and perhaps even earlier, visitor after visitor performed this feat, catching fish from the cold lake and cooking them on the hook. Hayden Survey members did it in 1871, and the next year they named the spring "Fish Pot" or "Hot Spring Cone." Later names were "Fisherman's Kettle," "Fish Cone," "Fishpot Spring," "Crater Island," and "Chowder Pot." The name Fishing Cone came about gradually through the generic use of the term in guidebooks.

Years ago, someone stepped on the cone and caused a hole which stopped the cone's eruptions.

The cooking-on-the-hook feat at Fishing Cone soon became famous. For years, park Superintendent P.W. Norris (1877-1882) demonstrated it to incredulous tourists, and in 1894 members of Congress hooted at their colleagues who described the process. A national magazine reported in 1903 that no visit to the park was complete without this experience, and tourists often dressed in a cook's hat and apron to have their pictures taken at Fishing Cone. The fishing and cooking practice, regarded today as unhealthy, is now prohibited.

Fishing at the cone can be dangerous. A known geyser, Fishing Cone erupted frequently to the height of 40 feet in 1919 and to lesser heights in 1939. One fisherman was badly burned at Fishing Cone in 1921.

There was a guide leading a group and she asked how new trees could be growing in this area. None of the adults knew the answer but a ten year did. The poop from bison provides nutrient material so it is the perfect place for pine seeds to germinate in.

Black pool

In 1935, Chief Park Naturalist C.M. Bauer named Abyss Pool, a hot spring, for its impressive deepness. Bauer may have taken the name from Lieutenant G.C. Doane's 1870 description of a spring in this area: "the distance to which objects are visible down in its deep abysses is truly wonderful". Abyss Pool may also be the spring that visitors referred to during the 1880s as "Tapering Spring" because of its sloping walls.

This pool is dying since someone dropped a coin in it.

Lower snow amount on the drive to Mud Volcano

Mud Volcano

When explorers first discovered Mud Volcano in the 19th century, the rumbling eruptions could be heard half a mile away. Mud Volcano shook the ground and flung mud into the treetops. The volcano later blew itself apart and is not as active for today’s visitors.

You can hike a short (less than a quarter mile long) boardwalk to see Dragon’s Mouth Spring and what remains of Mud Volcano.

As you step out of your vehicle at the trailhead along the Yellowstone River, you won’t be greeted by pine fresh mountain air. Instead you’ll be smacked in the face by a rotten egg smell caused by the hydrogen sulfide gas that escapes from the ground in this area, atop a resurgent dome in the magma chamber of the Yellowstone Caldera. It is worth tolerating the smell to see all that the Mud Volcano Area has to offer.

Sulfur is the source.

The Smell

Hydrogen sulfide gas rising from Yellowstone's magma chamber causes rotten egg smell.

The Mud

Microorganisms, or thermopiles, use this gas as a source of energy, then help turn the gas into sulfuric acid. sulfuric acid breaks down the rock and soil into mud.

The Colors

Many of the colors you see are vast communities of thermophiles, but some of the yellow is pure sulfur.

When iron mixes with sulfur to form iron sulfide, gray and black swirls sometimes appear in the mud.

This was the first location that had information about the bison.

The bison was neither bothered by the people, steam, steep slope or the smell. The bison only wanted to feed.

Dragon's Mouth

Dragon’s Mouth is a hot spring. Located to the left just down the boardwalk from Mud Volcano, Dragon’s Mouth Spring boils out of a deep cave. Gasses and steam are released deep in the cave, creating pressure bubbles that explode against the roof of the cave. As this occurs, it creates a kind of booming and gurgling noise that is echoed through the cave and can be heard from the boardwalk. The sound resembles the growling of an animal. Due to the high temperature of the water, large amounts of steam rise from the mouth of the cave, giving the impression of smoke billowing from the mouth of a dragon. Dragon’s mouth has captured the attention of travelers since the early days of the park, and continues to do so today.

An unknown park visitor named this feature, perhaps due to the water that frequently surges from the cave like the lashing of a dragon’s tongue. Until 1994, this dramatic wave-like action often splashed water as far as the boardwalk. The rumbling sounds are caused by steam and other gasses exploding through the water, causing it to crash against the walls of the hidden caverns

Black Dragon Cauldron is a boiling mud pot, similar to the Mud Volcano. While Mud Volcano is now just a pool, having blown away its volcano top in 1872, Black Dragon Cauldron did not exist before 1948. It exploded into existence sometime before June of 1948, knocking trees down and showering the surrounding forest with mud.

Many birds and bison in this area.

I was surprised to learn white pelicans live in this part of the park.

This bison enjoyed kicking up the sand. Then, he would roll around in the sand. He kept doing this over and over. Amusing to watch.

Beautiful scenery in this part of Yellowstone.

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