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Riverside Geyser - August 1, 2013

In addition to trained geologists and the National Park Service, the Yellowstone National Park geysers are monitored by the  Geyser Observation and Study Association (GOSA).    According to The Geysers of Yellowstone, by T. Scott Bryan, Riverside Geyser is actually more regular than Old Faithful Geyser.  

The geyser was named in 1871 but there was some disagreement as to what actually constituted Riverside Geyser. Some people used the name Riverside for what is now called Mortar Geyser.  In any case, Scott reports it became regularly active in 1883.  

Riverside is an apt name.  It’s found on the banks of the Firehole River in the Upper Geyser Basin of Yellowstone, a short hike from Old Faithful.  Scott reports it is from an isolated spring and as a result, the actions of other geysers do not affect its eruption - therefore the great regularity.  

As you approach the viewpoint of the geyser, you’ll see a hand lettered sign of potential eruption times.  Historically, the intervals of eruption were reported by Scott as 5 1/2 and 8 1/2 hours but more recently, the average is every 6 1/2 hours.  The sign posts the possible time of eruption but you can wait plus or minus an hour on that eruption although the average is 30 minutes off the scheduled time.  The day we were watching for the eruption, it was 45 minutes off the scheduled time.  

Scott describes the structure as somewhat like a chair.  The main vent is akin to what the edge of the seat of the chair would be.  Back in the seat are two minor vents.  What would be considered the back of the chair is a large old vent which may have been the main vent at one time.

Prior to eruption, you’ll see an increase of water flow over the front edge of the “chair” and then some activity of the minor vents and then a boiling effect of the main vent.  The old vent will also sometimes begin to spill water out into the river as a precursor to the eruption.

At first, it seemed it would never erupt and then, as you can see by the video, it started before anyone realized it.  Scott reports the height of the water column as much as 75 feet maximum and the eruption continues for approximately 21 minutes.  What follows the eruption is a short steam phase of no great intensity.

I can safely say the eruption was worth the wait!

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