A thermal area in the park that attracts me strongly and that I think is underrated in general is Mammoth Hot Springs. Nineteenth-century visitors were sure it would sometime soon be turned into a spa or sanatorium, but fortunately that didn’t happen.
Before soaking in the hot pools became strictly forbidden, lots of people did it. Park hotels did not provide hot showers in those days. Belgian travel writer Jules Leclercq visited in 1883 and experienced “supreme satisfaction plunging into a basin whose waters were an exquisite 30ºC [86ºF]. My bath was a meter deep. The siliceous efflorescence that lined the interior walls seemed like velvet cushions. . . .” until he noticed water in a neighboring basin suddenly rising. It happened that his clothes and towels were in that basin. “The proximity of the hotel consoled me in my misfortune,” he concluded.
Lacking a volunteer organization such as the Geyser Observation and Study Association that keeps good track of the geysers in and around the Old Faithful area and Norris, Mammoth-lovers mostly have to find out what is happening there for ourselves. Mammoth’s springs and the terraces they create are always changing. The ones I found most active this August were Grassy Spring and its very new (probably as yet unnamed) neighbor; Canary Spring; and Narrow Gauge Terrace.
In the twenty years I’ve been observing it, the hot water activity in Canary has gradually migrated from close to the hillside just below the Grand Loop Road out to the north.
The terraces Canary is building are amazingly high and beautiful. Here’s what I saw on the morning of August 15, 2014:
Near the steps leading down to Canary is a good place to observe how newer springs can begin to form terraces by depositing a thin layer of calcite ice on top of still, level pools of hot water; with time tiny delicate terracettes form around the pools. Eventually these will build up to be impressive terraces, too—and the boardwalk will have to be moved again!
An area not shown on the Yellowstone Association pamphlet map at all but described in Yellowstone Treasures is my other favorite at Mammoth, the extremely active lower terrace formation at Narrow Gauge Terrace. Deeply ensconced in tall trees, the growing terraces are almost impossible to photograph well. It was very dark there in 2009, but my friend Suzanne Cane got a very good shot in June 2013.
This year, the active springs and color from them cover about 300 degrees of a circle. My Narrow Gauge notes: “Building a throne for itself. One large dead tree fully knocked over at south end. No sound here but the musical bubbling at several pitches from various outlets.” Magical!