Norris Geyser Basin
Predicted Geyser
There is only one predicted geyser at Norris Geyser Basin, Echinus Geyser. Echinus Geyser's predictions are posted at the Norris Museum. Most of the time, Echinus is the star performer at Norris.
Echinus Geyser has been a real crowd pleaser. (Unfortunately, it didn't always live up to its reputation in 1998, when it had many aborted and wimpy eruptions. As of February 1999, Echinus was being described as fairly weak and erratic. Intervals were close to 90 minutes, durations were around 4 minutes, and maximum heights were only about 35 feet. Eruptions were preceded by about 20 minutes of overflow. Hopefully, it will improve later in 1999 but that may just be a pipe dream. Echinus has been known to change its character and strength greatly over the history of the park. We appear to be observing one of these changes.) When playing well, it is not uncommon to hear first time observers comment that they've enjoyed Echinus more than Old Faithful. It is possible to get closer to Echinus than to any of the other predicted geysers. This coupled with the wildly bursting play of Echinus makes it a treat to watch.
Echinus is a fountain-type geyser. Its maximum height is about 80-125 feet but most bursts are less than this. Its duration ranges from a minute to over an hour, though, most eruptions last between 5 and 15 minutes. Its intervals range from 20 to 80 minutes. Given Echinus Geyser's great show and its relatively short interval, it is worth waiting for even if you don't know the next prediction.
Echinus is the largest frequently active acid geyser in the world. Unlike most geysers in Yellowstone and around the world which tend to be alkaline in nature, Echinus, along with most of the other thermal features at Norris Geyser Basin, is acidic in nature. The water in Echinus is reportedly about as acidic as lemon juice.
Acid affects the formation of sinter deposits around the geyser. Because acid water can carry more dissolved silica than alkaline water, the sinter deposited from acidic water forms faster than sinter deposited from alkaline water. Also, the sinter deposited by acid water tends to look spiny. This spiny character is the reason for Echinus' name. Early explorers thought the tiny spiny formations found on pebbles around Echinus looked like sea urchins or echinoderms. Hence, the name.
Since Echinus bursts in all directions and the benches around the geyser are so close to the geysers, often some visitors will find themselves sprayed with water during the eruption. Don't worry, the water won't hurt you. It has cooled from its superheated temperatures as it has traveled through the air and is no longer dangerously hot but only warm. Also, the acid level at Echinus and the presence of other harmful chemicals, such as arsenic, are low enough that they do not present a danger to you. The same can't be said about your glasses and camera lens, though. The high silica content in the water means that if the water is allowed to dry on a glass surface, it will leave a permanent mark. Be sure to clean any water off of your glasses or camera lens. Otherwise, you'll have a permanent and unwanted souvenir from your trip.
What to look for:
After an eruption, the pool drops low into the crater. Some years the pool will drain completely, other years it will only drop a half dozen feet or so. Once the pool has stopped dropping it will almost immediately begin to very slowly rise in preparation for the next eruption. You can gauge the pools rise by watching a rock in the crater and noting the water level. Some years, the water has needed to overflow from the crater before the eruption will start but most years, it sits below overflow when the eruption starts. In general, the water level needed for the eruption to start stays about the same from eruption to eruption. Thus, with a little practice, or with the help of one of the rangers, you should be able to tell how full the crater needs to get before the eruption will start.
When the water is nearly to its highest level, bubbles will start rising towards the back middle portion of the crater. The boiling will get larger and eventually appear to move toward the center. At this point the eruption is very near. The boiling gets stronger, the pool starts rocking and then the geyser starts bursting.
It is not possible to tell how long the eruption will last. At certain points early in the eruption, the eruption will fade, at the nine minute mark for instance, at these points, the eruption may end or it may pick up again and continue.
Truly long eruptions, greater than 20 minutes, appear to tap into another reservoir of water and heat. In these eruptions, the strength of the eruption suddenly increases, the water turns murky and tests show that the water temperature increases and the water chemistry changes. Some years, these long eruptions are fairly common, other years, the eruptions are rare or nonexistent.
Just like Old Faithful, the interval to the next eruption of Echinus can be predicted based upon the duration of the present eruption. Unlike Old Faithful, the prediction requires some calculation to get a correct answer.
Comments and Questions are Welcome
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