The Upper Falls Geyser Basin

 The Upper Geyser Basin is located close and includes the Old Faithful Geyser contains a number of hot pools and geyser. In fact, this active geyser area contains over 25% of all geysers in the world. Again, this activity is due to the geothermal activity caused by volcanic and earthquake action. A bit separated from the rest of the Upper Geyser is the Black Sand Basin geyser area which we explored.

 Our first stop was at the Cliff geyser, located here on the banks of Iron Creek. The geyser does not erupt on a regular, so we were not surprised to see it just bubbling away.

Shortly after, while walking on the geyser walkway, we happened to turn around and sure enough, Cliff Geyser was erupting away! It was very cool as this geyser erupted up to 40' and we were delighted to have seen it.

I believe this is called Rainbow Pool, and holds water in the 160 degree range. Apparently, this has erupted in the past, with the last know eruption being in 1973. Today, the pool is still great to see, even if it does not erupt.

 Iron Creek runs through the Black Sand Basin and it is really an interesting contrast to see the steaming hot geyser water drain into the very cold creek water. According to history, early explorers would catch trout in the cold creeks and drop them into a hot pool to cook them. Pretty convenient.

  A short way further up the walkway was Emerald pool, which was a gorgeous pool containing 155 degree water. The pool is about 25' deep and features beautiful, clear, emerald colored water.

 Here, it is easy to see why this is called Emerald Spring. The deep emerald color comes from the very hot temperatures and as it cools, the various algae can grow and yields the interesting coloring around the edges.

 This is a great place to walk around the geysers and see many different kinds of hot water pools and geysers. Since the Black Sand Basin is across the Grand Loop Road from Old Faithful, it seems to receive far fewer visitors than the rest of Upper Geyser Basin which is located right at Old Faithful.

 The biggest hot water lake in the basin is Sunset Lake which holds hot water of 180 degrees -- no wonder there is so much steam in the air over it. With a depth of 24', the lake does surge occasionally, pushing about 3' of excess water into Iron Creek. We did not see this rare event, but still really enjoyed the Black Sand Basin.