Do you like it when nature gets weird? Like, fried-on-acid-tie-dyed-reflections-of-passing-clouds-in-the-boiling-limestone-terrace-water weird? Well, if you want to see some of the weirdest scenery nature has to offer in a place that’s jam-packed full of weird stuff, stop at Grand Prismatic Spring to see Yellowstone’s biggest and most colorful hot spring.
Of course, I don’t mean to be flippant about the confounding and exceptional scenery that’s crammed into every inch of this hike. This is a very, very, very famous place that’s only a few notches below Old Faithful, Mammoth Hot Springs, and Yellowstone Falls on Yellowstone’s very deep Greatest Hits album.
And of course, it’s very famous for a reason. Not only is the spring the largest hot spring in the park, but the temperature gradient from its intensely hot inner blue eye produces a prism of colors as the water cools outwardly, with a variety of bacteria and algae creating new colors with every inch and every degree drop of water temperature.
There are several other notable highlights surrounding the spring. The Excelsior Geyser Crater, formerly the Excelsior Geyser, spills millions of gallons of super-heated water into the aptly named Firehole River every day. The geyser was once one of the most impressive geysers in the park until it went dormant. Then, in 1985, the geyser erupted over two days, creating a crater that’s now filled with roiling, boiling blue water. Of course, the water in hot springs isn’t actually blue. It appears blue when the water is so hot that it destroys all life within its waters, leaving the waters to reflect the blue from the sky.
Also present along the route are the Opal and Turquoise Pools, a pair of surreal, brilliant blue hot springs that also spill forth hot water. Surrounding the margins of the springs are numerous terraces created by minerals from the spring water. As the terraces cause the water to pool, the water deposits its minerals, further reinforcing the terraces. These terraces reflect the sky, but not in the pure blue from the springs. However, the mirror images are sure to capture the imagination of photographers.
Speaking of photography, this is an absolutely incredible place to take pictures. I don’t usually dole out photography advice, but I recommend that you bring a good camera with a good zoom lens. It’s impossible to get too close to the springs (and it’s your death if you attempt it), so a good zoom lens will help you capture some of the details that make this such a fascinating place.
The short hike is very easy to follow. Simply stay on the boardwalk to complete a lollipop-loop that passes the Opal and Turquoise Pools, skirts the northeast end of Grand Prismatic Spring, and then returns along the Excelsior Geyser Crater. Walk slowly and stop often, as every inch yields some new oddity caused by the combination of heated water, geology, and micro-organisms. The only diversion is a viewing platform that allows you to peer into the waters of Excelsior Geyser Crater at 0.45 mile.
The trail is a well-traveled boardwalk that is impossible to miss. DO NOT STEP OFF of the boardwalk, as it could lead to severe burns and extensive damage to the habitat.
The nearest campground is at Madison Campground, which lies 10.3 miles north of the Grand Prismatic Spring parking area.
From the park's west entrance in West Yellowstone, head east for 14 miles on US-191 to Madison Junction. At the junction, turn right to head south on US-191/Grand Loop for 10.1 miles to the Grand Prismatic Spring parking area.