Percolator Geyser

Established in 1872, Yellowstone was America's first National Park, and what a place to start. Yellow stone has some unique hydrothermal and geologic features, with two thirds of the world's active Geysers. Formed when a massive volcano erupted around 600,000 years ago and created a crater around 80km wide. The area inside the crater, or Caldera, is closer to the active lava lake below the surface, the hot spot, which heats water rapidly forcing it through a series of natural pipes up to the surface, increasing in pressure along the way. This is the science behind it, but really what we see as we go along the park is some forest, grassland and rivers and every here and there some steam coming up between trees or a river covered by steam!

The first thing we noticed was the cold. We drove through a snow storm to get to where we are camping at just over 2000m and at night it drops to under 5°C. We were not prepared for this, luckily the campsite had an extension lead so we could power the mini heater the van hire people had given us, we had really not expected to need it, so we didn't freeze in the night.

After a frosty morning and once we thawed we started our journey into Yellowstone in the upper Geyser Basin. A well maintained walking trail which passes by some of the most predictable Geysers in the world, some with time estimates for their eruptions down to the minute. We were lucky enough to catch the Grand Geyser blow as it shot boiling water and steam up to 100m in the air. Lucky enough indeed as the predictions sometimes are +/- 1 hour... A long wait when there is so much to see in the park!

We followed the trail through the woods and had some close encounters with squirrels, marmots, a wolf and some bisons, which we found grazing right next to the path. We made it back in time to finish our day with the most famous geyser in the world, Old Faithful, so named because she goes off roughly every hour, not the biggest or most extravagant eruption but the regularity of it is what's most impressive.

On the path, in between geysers, there are hot springs. These are great as there is no timing involved, just gazing into the different colours that each has. Some are monochrome, just a deep blue or turquoise or transparent, and others have a mix of blues, oranges, greens and white. These are the ones on the advertising pictures for Yellowstone and we were doubtful that we would actually see those and for once they don't lie! Our pictures do not do them justice, they are really colourful! The science behind all these colours? The organisms that live in them. Depending on the water temperatures (usually quite hot, minimum 30C ) and acidity level only certain types of organisms can live in them and they give those colours.Read more