More Appealing than its Name: The Mud Volcano Exploration Walk in Yellowstone

September 2023

Date: July 20, 2020 and September 30, 2023

Place: Yellowstone National Park, Wyoming

Coordinates: 44.624691, -110.433234

Length: 1 mile

Level: easy

 

The last day in Yellowstone on both my 2020 and my 2023 trips involved visiting the same three places - The Yellowstone Falls, The Mud Volcano, and the Grand Prismatic Spring. On our 202o trip that day started with decamping and getting ready for the day's trip. During the morning preparations my elder chika encountered a lifer bird in the grass - a pine grosbeak, and her excitement soared to the sky. After breaking camp we went to theYellowstone River Rim Drive, where we took a short walk to Artist's Point to observe the Lower Yellowstone Falls. 

Pine Grosbeak

Driving south from Yellowstone Falls, the next obvious stop would be the Mud Volcano. The Mud Volcano is a relatively small basin but a very interesting one. On both my recent trips to Yellowstone, the July 2020 road trip with the youth and the September 2023 road trip with my sister we stopped at the Mud Volcano for some exploration. I describe both hikes here as they are fairly short. 

Mud Volcano Basin

There is a small loop boardwalk that surrounds the main basin area. There is also a larger loop trail higher on the hillside, leading to a few larger thermal pools. On my 2020 visit we hiked both trails, starting with the larger one. 

Our hike as captured by my GPS

We started our hike going west. Alkali vegetation grew right by the geothermal features but a bit higher up more ordinary plants were thriving, and some were blooming too. Wildflowers were blooming here and there within the grass and rushes.

Lupine, Lupinus sp.

The wildflowers at the Mud Volcano Basin weren't as numerous or as spectacular as I've seen on previous hikes in the area, but I didn't mind that. It only meant I didn't stop as frequently and I could keep pace with the rest of my party.

Many butterflies flew around the wildflowers. They were very active and were difficult to focus on. Ocassionally one would pause somewhere for a little bit and I could take its photo.

Azure Butterfly

Higher up the boardwalk trail I took in the view of the the green valley we walked along. The day was as beautiful as it could be. The weather was perfect and the colors brilliant. The beautiful day didn't smell like roses though. The smell was more fitting of a geothermal area, imbued with sulfur odor whiffing in and out in light waves on the air. 

Soon enough we approached the higher features that sourced the sulfur odors. Large bubbling thermal pools greeted us at the upper arch of the boardwalk. 

Small trail spurs led us to observation decks, overlooking the pools. It was interesting to see how different they were one from another, even when cat a close distance. One had almost clear water, and the others were of pasty, bubbling mud. 

Some of these pools reminded me of the Sulfur Works geothermal area at Lassen Volcanic National Park. The sheer scale of the Yellowstone geothermal features however, was unsurpassed by anything else I've seen. 

The upper boardwalk loop was near a few other geothermal features. Some of the pools were clearly not hot, or at east not as hot - vegetation was growing right at the water. Little gas bubbles rose to the surface, giving the pool a soda-like appearance. Perhaps these were carbonate bubbles which would make this pool a true soda pool. 

Another mud pool seemed unmoving at all. It was covered with a  film of muck - likely microorganisms, either bacteria or micro algae.  

In between the pools there were more wildflowers blooming. Even the small and modest willowherb looked more festive blooming in the scenery of the volcanic basin. 

Willowherb

From the highest point of the trail we had a nice view, not only of the lower part of the basin but of the area beyond it - the blue strip of the Yellowstone River and the forest that belted it. 

Down below us was the largest mud pool of the Mud Volcano basin. Steam rose form the corner of the pool. A sign post said this was the Mud Geyser - a geyser that erupted only twice within recorded history. We watched it for some time but it didn't erupt for us, so we moved on. 

The boardwalk trail led us downhill toward the lower part of the basin. Things were abut to get a lot more exciting there, and not because of the geysers. Not knowing that however, I still enjoyed the calm day and the lovely wildflowers along the trail. 

Cinquefoil, Potentilla sp. 

We descended back to the lower area of the Mud Volcano basin right to the part called, "The Boiling Hillside". This area used to be forested but a series of earthquakes in the late 70's caused the rise of thermal water through the earth there, which killed the trees. the dead, fallen trees are strewn all over the place there, above the boiling pool. 

The Boiling hillside

That by itself was an interesting sight, but what made it more exciting was a large bison bull that lowed its way up that hillside, completely unconcerned with the possibility of sliding down into the boiling water below. 

We turned to walk the smaller, lower loop of the Mud Volcano. A dust-bathing bison, also male, was enjoying himself in the middle, in complete disregard of the numerous people observing him from the elevated trail.  

Another bull bison stood very close to the board walk. Human visitors grouped by the rail, trying to get the perfect shot of the massive beast. 

The bison soon delivered the goods - he too dropped into the sand and started rolling in it with clear excitement. The reason turned out to be that the bison from the other side was approaching. 

What followed next I didn't catch on camera - the two bull bisons got engaged in a pre-fight dominance show off that involved getting onto the boardwalk. All the humans that were there including myself and the youth in my group quickly retreated t a safe distance. By the time I got a clear view of the fight scene the loser was already retreating up the valley to the higher basin area. 

We didn't see any female bison herd nearby. The winner bull bison celebrated his victory by resuming his dust bathing activity. 

Calmness returned to the lower Mud Volcano basin. At least for the time being, only the thermal pools bubbled lively. People, including us, resumed our quiet stroll along the boardwalk. 

Lower Mud Volcano basin

We got to enjoy the Dragon Mouth geyser as the warm steam swirled around toward us, before returning to drift to the other side. 

Naturally, my eyes were attracted to the yellow spot on the other side of the pool, near the dragon's mouth - a large patch of yellow monkeyflowers. 

The lower, smaller boardwalk loop took us almost as long to walk as the upper, because of the bison excitements and also because this small area holds a lot of interesting features in it. I compare the photos I took then with photos I took of the same features three years later and find it fascinating to see what had changed and what stayed the same.

Lower Mud Volcano Basin

After completing the Mud Volcano Basin loop we found a place to have a picnic lunch and moved on to the Grand Prismatic Spring for our last Yellowstone hike for that trip.

Tiny Mud Spring

Three years later, on September of 2023 I was back in Yellowstone with my Sister. We had a shorter time there and didn't get to see all the places that I visited with my chikas and their friends in July of 2020. The lower Mud Volcano loop however, was one of the places we did visit and my sister found it as fascinating as I did.

Lower Mud Volcano Basin, September 2023

The bison were there on this visit as well. I guess they love this area. This time however, they did not provide any action. They weren't close to the boardwalk but remained up the hill. There were a couple of large bulls there, and behind them a herd of bison cows, well tucked in the trees. It was impossible to estimate how many bison were in that herd, and I couldn't get a clear photograph of the females hidden in the background.

Still, a bison is a bison. My sister, who has never seen one from our trip to Yellowstone, couldn't detach her gaze from these royal beasts. She did so eventually, to look at the geothermal features and to appreciate them with all of her senses, including smell and sans touch.

Mud Spring

As we walked around the larger pool in the middle of the boardwalk loop I noticed a clamp of cattails in one corner. I didn't recall seeing them there on the previous visit and when I checked my older photos I saw that indeed they weren't there at the time. Nature is in constant change. 

The water level in some of the areas was lower and the mud shaped itself into interesting and eye-pleasing patterns.

The steam emanating from the pool below the boiling hillside was much more visible. I thing that wasn't because there was more steam than in July of 2020 but because the air that day was considerably cooler, not to say cold even.

No bison were climbing the boiling hillside. I could see however, that the trees were making a comeback - there was a slow regeneration of the forest patch there. Perhaps the soil closer to the surface was cooling down.

 Revisiting any given place again can reveal that Nature is always in flux. In geothermal areas however, that change seems to happen faster and in more unexpected ways. I wonder how this place would look like on my next visit in Yellowstone. I hope it won't take me too long to go there again.