Yellowstone: Midway Geyser Basin

We're not through with September 20th yet. After our visit to Old Faithful and our hike to Mystic Falls, we drove the short distance to Midway Geyser Basin.

Footbridge over the Firehole River to Midway Geyser Basin

Can you see how the Firehole River got its name?

Excelsior Geyser Crater in Midway Geyser Basin
 

Once the largest geyser in the world, with eruptions up to 300 feet,  Excelsior is now a productive thermal spring, presently discharging 4050 gallons per minute. Numerous vents boil and churn the water within the crater, covering it in a dense layer of steam.

The main feature in Midway Geyser Basin is the Grand Prismatic Spring, which is the largest hot spring in the United States. It measures approximately 370 feet in diameter and is over 121 feet deep, with a water temperature of 147-188 degrees Fahrenheit. Its steam produces a blue haze that rises several feet above the water. The brightly colored algae surrounding the pool gives the impression of a giant prism.

 

These next three photographs are of Grand Prismatic Spring:

 

The views from the boardwalk just can't give the full effect of Grand Prismatic Spring. There is a footpath up the hill on the back side of the spring that allows a view of it from above. We just didn't have the energy to tackle that steep path at the time we were there. Maybe next time.

Another thermal feature in Midway Geyser Basin

Turquoise Pool in Midway Geyser Basin

More to come from this day in Yellowstone on the next post.