In July 2018 I visited Yellowstone National Park in northwestern Wyoming again for the first time since I was 15 years old in 1983. It’s quite a different experience to visit a place as an appreciative adult rather than as a moody teenager. Not to mention the fact that my photographic skills are much better now than they would and could have been back then. 35 years is almost half a lifetime, essentially.

The Cliff Geyser erupts at the edge of the Firehole River as it flows through Black Sand Basin in Yellowstone National Park.

Of course one of the primary reasons that millions of visitors go to Yellowstone is to view the thousands of geothermal features within the park. One of these is called Cliff Geyser, which sits on the banks of the Firehole River just a couple of miles west of Old Faithful. Water at 192 °F (89 °C) jets up to 40 feet (13 meters) into the air in cycles lasting anywhere from 30 to 90 minutes before settling down for several hours. I was not aware of the long pauses between eruptions, and as such it was simply fortunate that I ended up being there at the right time.

Cliff Geyser boils over into the aptly-named Firehole River. The hot spring was named for the rim of “geyserite” (travertine) that separates the pool from the river right at the margins of a steep embankment.

Also of interest is the fact that the Cliff Geyser also goes through longer-term cycles of activity and dormancy. When in an active phase, the geyser erupts two to three times a day. But then it goes dormant, and that phase can last for anywhere from several days to several weeks, with periods of several months having been recorded in the past. I suppose that makes it doubly-lucky that I was there at the right time, because there was no guarantee that it should have been visible in the half hour of time that I was at Black Sand Basin on my vacation.

The Firehole River flows through terrain populated by numerous hydrothermal features draining into it. As a result, water temperatures in the river have been measured as high as 86 °F  (30 °C) and average  9 to 18 °F (5 to 10 °C) higher than areas upstream of geothermal influence. The orange coloration is due to bacterial mats that live in the warm waters.

Old Faithful, which is the world’s most famous geyser located only a few miles away from here, is unusually reliable. The norm for most geysers is to be unpredictable and to operate on irregular cycles that defy neat fitting into scheduled time frames. In this regard Cliff Geyser is more typical of these hydrothermal features. One of the great mysteries of geysers is the complexity of their geology and the unseen and hard-to-study factors that drive their behavior. Despite the challenges they present to science, there’s little doubt that their beauty can inspire, fascinate, and amaze us.

A view of the Cliff Geyser erupting about 10 to 15 feet (3 to 4 meters) high across the Rainbow Pool.

Cliff Geyser churns vigorously in the distance while a smaller vent whose name I don’t know bubbles in the foreground.