The periodic geysers in Yellowstone work kind of like natural pressure cookers. First, rain and melted snow soak into the ground and collect in spaces between underground rocks. These rocks sit above a hot area deep below the surface, where magma from Yellowstone’s volcano heats everything up. As the water goes deeper, it gets hotter—hot enough to boil—but the pressure from all the water and rock above keeps it from turning into steam right away.
Eventually, the water gets so hot that just a little bit starts to boil and turn into steam. That steam pushes on the water above it, forcing it up through a narrow passage in the ground. As the pressure drops, more of the hot water suddenly turns into steam, causing a powerful burst of steam and hot water to shoot into the air. That’s the geyser eruption you see.
After the eruption, the underground space is mostly empty, so it fills back up slowly with more water. The rocks heat that water again, and the process starts over. Each geyser has its own timing, depending on how fast it refills and heats up. That’s why some, like Old Faithful, erupt often and predictably, while...
Read moreThis Geyser is nothing short of amazing. The day I saw a great eruption from Castle it out preformed Old Faithful. The eruption lasted for an estimated at least 15 minutes, maybe 20, no exaggeration. Then you have the spouting of the eruption that is steam for longer. Castle Geyser erupts 2 times a day, and they can't quite pinpoint the eruption time exactly. When I was there the estimated time of eruption was an hour and a half long. So you have to either walk to the geyser and read the sign in front of it or talk to park staff and find out. After you get the estimated time walk around the area of the upper geyser basin until you see it start to bubble up hard. When you see the classic action of a geyser about to erupt get over to Castle because it is extraordinary to say the least. Or you can also just sit by it and wait. You absolutely won't be sorry when you experience...
Read moreThis is a beautiful geyser a short hike away from Old Faithful. It is a much larger and older geyser than Old Faithful but it only erupts about twice a day so it is much harder to see in action. Even if you don't see it erupting, it is still worth visiting. There is no easy access from tour buses so the crowds are always much smaller. The walk to the geyser passes many smaller thermal features which are all very interesting to see. The park staff try to predict the eruption times at Castle but it tends to be slightly less accurate than the Old Faithful predictions. Even if you don't see a full eruption, it isn't uncommon to see small...
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