Old Faithful near the peak of its eruption in Upper Geyser Basin, Yellowstone National Park, Wyoming. Old Faithful is the most famous geyser in the world, due to its regularity (must be taking its Metamusil). When we were there, the eruptions were approximately 90 minutes apart. The height of the eruptions averages 145 feet at the peak. The eruption we observed lasted about three minutes. Some scientists think the geyser could seal itself up at some point, as the constrictions in its plumbing may continue building up more silica to the point that the water and steam can no longer get through. It has two constrictions, one about 22 feet down and another about 70 feet down. This is known because they sent a tiny camera down on a probe line some years ago. The difference between a thermal pool and a geyser is that the pool's plumbing has no constrictions, so water can more freely circulate. Hot water and steam rise to the top, cool and then are drawn back down. Molten magma underlies much of Yellowstone and it heats the water and steam to a super heated point. Because of the constrictions in geyser plumbing, the pressure builds below a constriction until it becomes too great to be contained and it then erupts. Old Faithful is quite spectacular and nearly everyone who visits the park sees it because it is quite near the visitor center and has nice boardwalks and seating for observers. Other geyers eruptions can be more spectacular, but they require a longer walk to get to them and they may not be predictable or they may erupt very infrequently. The day we visited the Upper Geyser Basin, the Castle eruption was quite a bit larger and lasted much longer. The Beehive eruption we witnessed was also more spectacular, although it lasted about the same length of time. We were really lucky to see both Beehive and Castle, as they aren't as regular and their eruptions are less frequent. Some geysers erupt straight up, while others erupt in a more fan-shaped fashion. Pool geysers erupt in the fan-shaped fashion. Geysers with cones tend to have eruptions that go more straight up. Of course, the amount of wind during the eruption will affect the spread of the steam and water.
I appreciate the comments on my shot of the alliums. Have a great day!
old faithfulgeyserupper geyser basinyellowstoneyellowstone national parknational parkwyomingnaturelandscapethermalsteam