Here's a map for reference. We started at Old Faithful Geyser (in the bottom right) and walked northwest along the Firehole River towards Morning Glory Pool (about two-thirds of the way towards the upper left.)
Geysers, geysers, geysers.
Henry and Malcolm take in Crested Pool.
The Firehole River.
South Scalloped Spring.
Dead trees on the hill above Grand Geyser. The shifting geothermal heat and chemicals occasionally kill off stands of trees, leaving them as bleached guardians all about the basin.
Next we came to Grand Geyser, which is the largest predictably erupting geyser in the world with a height of 150-200 feet during a typical eruption. Grand Geyser erupts once every 10 to 12 hours as part of a complicated sequence involving nearby Vent and Turban Geysers. It's a bit difficult to predict in the field, but it usually coincides with an eruption of Turban Geyser, which is a small geyser that erupts once every 18-20 minutes. So, if you see a full pool of water in Grand Geyser, it's worth sitting and waiting to see what happens. We joined the gathering crowd....
A spring and pool, name unknown.
Back across the Firehole River.
We then came up to the Giant Geyser Platform. When Giant Geyser erupts it goes for up to with an hour with a stream shooting more than 250 feet into the air. Unfortunately, it's erratic and alternates between erupting as often as once every few days to going dormant for years at a time. Giant Geyser's most recent eruption was in January 2010, but even in its dormant periods it's still an active geothermal feature that often spurts forth a small bit of burbling water.
Bijou and Giant Geysers.
Another pretty little hot spring, name unknown.
Then, looming out of the steam and mist we came upon an active eruption from Grotto Geyser:
Monique and John at Grotto Geyser.
The woman to our right was a fixture for us on this walk. We nicknamed her "Bear-Bell Lady" because she wore a pair of the little bells that hikers wear in the backcountry to try to keep from being eaten by grizzly bears. I have doubts about their effectiveness, though, because after a few hundred yards walking along with the constant jingling I developed the urge to feed her to a grizzly bear.
On the bright side she kept us moving along briskly because we tried to be far enough ahead of her to mute the jingle. Unbelievably enough, we ran into her again the next day at Mammoth Hot Springs!
Spa Geyser ... this one looks like it would make a wonderfully comfy hot tub ... except that the boiling-hot water might be a wee bit warm for lounging about.
This is a little group of multicolored hot springs called Chain Lakes.
Another pool whose name I don't know.
The main Upper Geyser Basin walk ends at Morning Glory Pool. It's worth the walk!
The colors of Morning Glory Pool come from thermophilic bacteria that grow in the waters. The hottest waters attract the lightest blue colors, while the cooler waters at the edge grow the yellows, oranges and darker reds. I could stare into this pool for hours....
Thanks for joining us on our stroll along the Upper Geyser Basin! Here are your fellow walkers in front of Morning Glory Pool....
Monique and John.
Henry, Malcolm, and John.
Henry and Monique.
Next post: the rest of our Saturday afternoon in Yellowstone.