You’ve barely left the sulfur smell of Old Faithful behind, when you come upon another great excuse to enjoy an all-natural steam bath. Midway Geyser Basin is the second in a series of geothermally active areas (Old Faithful is in the Upper basin, and the lower basin is a few more miles up the road). Here, you get to see several great features, including the famously colorful (and surprisingly large) Grand Prismatic Spring.
From the parking area, you’ll cross a bridge over Firehole River. Steamy hot water flows from the geysers and springs, down the river’s banks.
Almost the entire path is a boardwalk, safely taking you across wet, hot, and unstable ground. Clouds of steam come and go, and at times, will overwhelm you. (By the way, once you’re back at your hotel for the night, you’ll smell the sulfur again when you shower–the odor gets in your hair!)
The first feature you pass on the loop route is Excelsior Geyser. It doesn’t do a lot of erupting anymore–these days it’s more like a spring, pumping out 4,050 gallons of water a minute. Long ago, it was the largest geyser in the world, but some violent eruptions back in the 1880’s must have changed Excelsior’s plumbing, and it stopped erupting for about 100 years. In 1985 Excelsior Geyser erupted for two days, then returned to a life of bubbly, steamy silence.
From there, you walk over ground that reflects the sky. Unfortunately, the sky wasn’t very exciting during my visit.
After seeing one tiny spring after another, back in the vicinity of Old Faithful, I was expecting Grand Prismatic to be about the same (I imagined that “Grand” referred to its colors, not so much its size). Instead, I found a spring so huge, I didn’t even know I was looking at it, at first. Grand Prismatic Spring is best viewed from the air, since the boardwalk doesn’t take you very close. The colors are intense, even with a cover of steam.
The looping boardwalk will take you back to where you started.
Note: This trip was first published in 2007.