The Mud Volcano area is one of the thermal areas in Yellowstone National Park. It has in the past proven to be one of the more volatile thermal areas in the park. It is composed of mud pots and steam vents, called fumaroles; steam and gasses like hydrogen sulfide—the source of the smell that most people compare to rotten eggs—bubble through the mud. Although there are no proper geysers here, the gasses make the mud appear to boil or even erupt.
Instructions
1. Drive to the Mud Volcano area. It is on the road between Canyon Junction and Yellowstone Lake. As you drive north on this road, it is not far past LeHardy Rapids on the Yellowstone River; as you drive south, it is just past the end of the large, open area called Hayden Valley. The area may be easier to find simply because it is so congested. The speed limit drops from 45 to 25 mph, and the traffic usually thickens. As you creep through the area, look for parking areas on either side of the road.
2. Park in the smaller lot to see Sulphur Caldron; the lot is more like a turnout. Sulphur Caldron itself can act as an introduction to the area. Like many features here, it is a thing of extremes. In this case, it is an extreme of acidity, Sulphur Caldron being among the most acidic of the hot springs in Yellowstone. The pH has been measured at 1.3.
3. Move to the larger parking lot, on the other side of the road and a short distance south. From here, you can set out into the Mud Volcano area proper. A loop trail, with some side trails, begins in the parking lot. You can start at either the north or south end of the trail.
4. Start at the south end, and it will take you up the hill toward Sour Lake, a large pool of acidic water. This loop hike is the only part of the visit that will be challenging for some people, since the trail is steep. It will take you past Cooking Hillside, where a swarm of earthquakes in the late 1970s changed the local geology and allowed greater heat to reach the surface, killing all the vegetation in this area.
5. Descend from Sour Lake on the other side of the loop trail to pass Mud Volcano itself and finish at Dragon’s Mouth Spring, a favorite of many visitors for the rhythmic bursts of water and steam that issue from the cave where the spring has its opening.
Tags: Sulphur Caldron, Volcano area, loop trail, National Park, other side, side road, Sour Lake
