The Black Sand Basin is located on the Yellowstone National Park’s ring road only 1.5 km northwest of Old Faithful. It is an isolated hydrothermal area with large hot springs and some small geysers, which got its name from some occurrences of black obsidian sand. I would have called this area White Sand! The Opalescent Pool is located close to the car park. I love this sight of the blue spring in the middle of the dead lodgehole pines and the white ground. The water from the surrounding geysers and springs contains large amounts of silica, which was absorbed by the tree trunks over time and is now reminiscent of white socks, why they are also called white »bobby sock« trees. Where there is no longer any water flowing, the silica also provides the white soil. Everywhere in Yellowstone National Park you will find the white ground.
The small stream Iron Spring Creek runs through the area, it has a shore dominated by the silica almost everywhere. The banks of the river are yellow to reddish only in places where hot springs flow into the river, which indicates the hot habitats of bacteria.
The special features of the Black Sand Basin, however, are the deep blue‐green Emerald Pool on the southern edge of the area and the two large blue pools on the west side of the river. The Emerald Pool is surrounded by a strong yellow border and has the typical red/orange drains.
On the way back from the Emerald Pool, the wooden plank path leads north. We got over the drain of the Rainbow Pool. Its red/orange colour has impressed me very much. In the background you can see the hot pool with its steam. It has a temperature of 161°F with a size of 100×130 and a depth of 27 feet.
In the direct neighborhood is the even bigger Sunset Lake. It has dimensions of approx. 145×191 feet and is even hotter with 180°F! I had to make a panorama here again to capture its dimensions at all. You might know — click on the image to view it large in all of its beauty:
Due to the many hot springs and some small geysers the air was filled with steam again and again. Every few minutes the Cliff Geyser on the banks of the Iron Spring Creek erupts. It erupts in small fountains, some of them are said to reach a height of up to 40 ffet. For us it was the first geyser we saw live (and in color) on stage…