Midway Geyser Basin, Flood Group
Flood Group adjoins Excelsior Group to the southwest. It can be observed from highway turnouts and from the Fairy Falls trail, but there are no trails leading into the group. Another excellent viewpoint was the top of Midway Bluff, wherefrom some of the following pictures were made, but it has been closed to access since 2016.
The eastern part of Flood Group, located on the east bank of Firehole River, is visually dominated by Circle Pool. On the slope directly above Circle Pool there is a large roadway turnout, the best position to observe features and activities within the group.
Circle Pool itself is a quiet hot spring, but close to its southwest rim Tangent Geyser is embedded in a fracture. Tangent Geyser is a very rare performer. In the RCN database it is listed as "Tangine Geyser".
South of Circle Pool lies the main geyser of Flood Group, Flood Geyser. It is a very frequent performer and plays up to 7 m (25 feet) out of a deep pool, lined with beautiful sinter bulbs.
Also on the east bank of Firehole River, but farther to the south beyond a river bend, Catfish Geyser is located. Approximately every 15 minutes the boiling water domes up a few feet.
Across Firehole River from Circle Pool another large, steaming pool catches the eye. This is West Flood Geyser, but unlike Flood Geyser it erupts only rarely and irregularly.
The meadows beyond West Flood Geyser to the west are home of several small geysers and hot springs. They can only be observed from a distance.
T. Scott Bryan designated an area west of Firehole River, where most of the small geysers are located, as UNNG-MGB-7. The next picture shows a section of it with a particularly high concentration of features. Among these is Tentacle Geyser, the structure looking like a stranded jellyfish in foreground left. Its rare eruptions may reach up to 3 m (10 feet) height.
Iris Pool is the largest among the hot springs in the meadows.
Nearly halfway between the other members of Flood Group and Excelsior Group lies the quiet Tromp Spring. In the field around Tromp Spring the traces of former roads can be recognized. At that time, its position next to the road was the main reason why Tromp Spring got attention and even a name.
