Though it’s not what the park is most famous for, Yellowstone is a supervolcano and the entire center of the park is a giant caldera. You can see the caldera boundary outlined in light purple in the map below. All of the geyser basins are located within this caldera. In my first Yellowstone post, I left off at the northernmost Norris Geyser Basin. From here, I’ll continue south through most of the rest of the basins.
Much of the road from Norris to the Madison Junction parallels the Gibbon River. At Madison Junction, the Gibbon River joins the Firehole River – which flows up from the south – to form the Madison River. These are the main waterways in this section of the park.
As we begin our journey south along the Gibbon River to Madison Junction, the first roadside attraction is the bubbling, colorful mud at Artists Paintpots, followed by Beryl Spring and Gibbon Falls.
The Firehole River then flows out of the canyon and meanders its way through wide open fields, some of which contain thermal features. This area is known as Fountain Flat. Many of these thermal features actually drain into the Firehole River, making the water fairly warm; this is where the river gets its name.
Continuing south, we reach the first in a string of geyser basins. First is the expansive Lower Geyser Basin, which encompasses Fountain Paintpot and Firehole Lake Drive. Fountain Paint Pot is a mud pot. Instead of hot water, mud is heated and bubbles up to the surface. It sounds kind of gross but it’s actually really cool, and the boiling mud makes a very strange gurgling sound. Iron and other minerals in the mud give it varying yellow, orange, and pink hues. Plus, there are hot springs and geysers here as well!
Firehole Lake Drive loops around a handful of hot springs and a few geysers, including two hot springs that are so large they’ve been dubbed Hot Lake and Firehole Lake.
The next attraction is Midway Geyser Basin, home to the largest hot spring in the US and third largest in the world – Grand Prismatic Spring. Grand Prismatic is enormous. It’s difficult to grasp its size because it’s so huge that it’s not possible to see all of it at once while walking through the basin.
However, there’s a trail behind Midway Geyser Basin that provides viewpoints of Grand Prismatic from a hillside. From here, the size as well as the brilliant colors of the hot spring are easy to see.
The colors of the hot springs in Yellowstone are related to the temperature of the water. Different species of thermophilic (heat-loving) bacteria are adapted to life in water of very specific temperature ranges, and it’s these bacteria that give the hot springs their vibrant colors. Blue and green bacteria thrive in water that is near the boiling point, while yellow and orange bacteria prefer slightly lower temperatures. If a hot spring is colorless, the water is likely too hot for even the most extreme thermophiles to survive.
Continuing south from Midway, we arrive at the small but pretty Biscuit Basin and Black Sand Basin. Biscuit Basin is home to the very dependable Jewel Geyser. It’s by no means the largest geyser in the park, but its eruptions are moderately tall and very frequent. I’ve probably seen it erupt every single time I’ve been to Biscuit Basin (and yet I don’t seem to have a good photo of it).
The most unique aspect of Black Sand Basin is the many hot springs and geysers right on the banks of Iron Springs Creek. I always enjoy the contrast of the colorful hot springs right up against the clear blue of the water.
Last but not least is arguably the main attraction of Yellowstone: Upper Geyser Basin and Old Faithful. Upper Geyser Basin is enormous. Everyone visits to watch Old Faithful, which erupts approximately every 90 minutes; however, Upper Basin is home to the largest concentration of geysers in the park as well as many beautiful hot springs. Of note are Grand Geyser, Castle Geyser, and Beehive Geyser. My personal favorite – Grotto Geyser – is also located here.
I feel like I shouldn’t have to say this, but clearly it needs to be said: Yellowstone is a fragile and wild place that should be treated with respect and reverence. It’s so fortunate that we’ve had the foresight to preserve these incredible features and landscapes as a national park. Too often, people seem to forget this, and it’s the careless actions of these few individuals that ruin things for us all. I wrote a whole post about this a few months back, so for now I’ll just end with this:
I absolutely love Yellowstone and it’s a place I encourage everyone to visit… but only if they can afford the park the respect that it deserves.