Biscuit Basin in Yellowstone National Park made headline news last week when a geothermal explosion of Black Diamond Pool sent visitors fleeing. The small geyser basin will remain closed for the rest of the summer. Geothermal explosions are not a rare occurrence in Yellowstone and, according to park geologist Mike Poland, happen as frequently as one or two times a year. Black Diamond Pool had previously experienced a steam, or geothermal, explosion in 2009 and Porkchop Geyser in Norris Geyser Basin exploded in 1989. In fact, at Biscuit Basin, the entire Wall Pool/Black Diamond Pool/ Black Opal Pool complex were created by steam explosions that occurred between 1902 through 1934, according to the book The Geysers of Yellowstone by T. Scott Bryan.

Biscuit Basin is one of my “go to” locations for sunrise when I have a book/print signing in the lobby of the Old Faithful Inn. The lead photo to this article depicts what was Wall Pool prior to the July 23rd steam explosion. Based on aerial photographs provided by the National Park Service, it appears Wall Pool and Black Diamond Pool are now one large pool and the Park Service, at least for now, has labeled it Black Diamond Pool. Above, Jewel Geyser is largest of a couple of small but regular geysers that can be found at Biscuit Basin. And below is Sapphire Pool, arguably one of the prettiest hot springs in Yellowstone. Though it sits only a few dozen yards from the Black Diamond Complex, based on aerial images, it appears unaffected by the event of July 23rd.