Grand Prismatic Spring

The Grand Prismatic Spring is the largest hot spring in Yellowstone and the third largest in the world (after Frying Pan Lake in New Zealand and Boiling Lake in Dominica).  The spring was first observed by geologists in 1871 and was named for its striking coloration, matching most of the colors seen in light dispersed by an optical prism: red, orange, yellow, green, and blue.

We first view the spring from a viewpoint at the Midway Geyser Basin, along the Fairy Falls Trail, then head over to walk on the boardwalk through the spring itself.

Fairy Falls Trailhead

Looking over at the Grand Prismatic Spring

We park along the road at the Grand Prismatic Spring (parking lots are full) and walk over to the boardwalks that loop through the area.

Approaching the spring

The bright, vivid colors in the spring are the result of sunlight being scattered by mineral particles in the water.  The spring often appears to have a blue haze hovering over it, caused by the steam reflecting from the blue of the water.  Bright orange heat-loving bacteria known as thermophiles populate the run-off channels.  These microbes contain colorful pigments that allow them to make energy from sunlight and thrive in the hot conditions of the spring.

Walking across the spring

Near the end of the walk, we pass a few pools and finish our loop.

Opal Pool

Turquoise Pool

What an incredible sight!

Old Faithful

Watching the Old Faithful Geyser erupt is a Yellowstone National Park tradition and it was such unique thermal features that inspired the establishment of Yellowstone as the nation's first national park in 1872.

Old Faithful is one of nearly 500 geysers in Yellowstone and is one of six for which the park predicts eruptions.  The geyser has lived up to its name, only lengthening the time between eruptions by about 30 minutes in the last 30 years.

Behind the Old Faithful viewing area is a series of boardwalks that weave around the geyser and into the Upper Geyser Basin, which is packed with other [smaller] geysers and geothermal features.

Passing by Old Faithful (before eruption)

Continuing past Old Faithful

Into Upper Geyser Basin

Hydrothermal features can be grouped into two general categories:  those with limited water (mudpots, as we saw in the previous blog) and those with a lot of water (hot springs and geysers).  After visiting the mudpots yesterday, we now proceed to the land of geysers.

Anemone Geyser

Field of geysers

Here are a few more of the geysers and other geothermal features we meet on our walk through Upper Geyser Basin behind Old Faithful.

Beehive Geyser

Heart Spring

Lion Geyser

North Goggles Geyser

Ear Spring

Beach Spring

Doublet Pool

Sponge Geyser

Pump Geyser

Infant Geyser

In addition to the beauty of the Upper Geyser Basin, we're here for Old Faithful and we return to the viewing area just before the next eruption.

Old Faithful getting started

Old Faithful (right on time)

The Old Faithful location in the park is not just about Old Faithful, but also other small geysers and hydrothermal pools of the Uper Geyser Basin with all its geothermal features and we appreciate and enjoy both.

Artists' Paintpots in Yellowstone National Park

Artists' Paintpots in Yellowstone is known for it's mudpots, which put on an intriguing show of splattering mud as they erupt.  Mudpots are acidic hydrothermal features with a limited water supply.  Microorganisms use hydrogen sulfide, which rises from deep within the earth, as an energy source to help convert gas to sulferic acid, which breaks down rock to wet clay and creates the area's distinctive smell of rotten eggs.

The area is covered by a one-mile (1.6 km) loop trail that enters a partially burned lodgepole pine forest then winds across the wet meadow on a boardwalk.  The hydrothermal area on the loop trail has colorful hot springs, mudpots, and small geysers with wet clay bubbling due to the gases escaping through the ground.

Artists' Paintpots

We start on the boardwalk to the paintpots and  enter the loop.

Boardwalk in

First views of paintpots

The Blood Geyser has a high concentration of iron oxide in the water, staining the surrounding rocks a rich red color.  The geyser has been erupting since 1882 and can erupt up to 6 feet (1.8 meters) and discharge 150 gallons (567 liters) a minute.

Blood geyser

Continuing through the paintpots

The hydrothermal system at Artists' Paintpots acts like a double boiler, with boiling water underneath the ground generating a hot acidic steam that heats the ground above it, causing the rocks to dissolve into clay.  The clay receives water from precipitation and snow melt, causing mudpot consistency and activity to vary with the season and amount of preciptation.

Mudpots

As the trail loops around to the other side, we get more spectacular views of mudpots and paintpots.

Looping around to the entrance

What a spectacular (and unexpected) walk through the beauty and geography of this fabulous hydrothermal display.