Maybe they'll need to start calling it Old Fickle.
Yellowstone National Park's most famous geyser, Old Faithful, has been slowing down of late. In 1997, the geyser erupted on average every 71 minutes. In 2006, it erupted every 91 minutes. Shaul Hurwitz, a researcher with the US Geological Survey, has found that drought is to blame.
Working with Stanford University statistician Ashish Kumar and two scientists from the National Park Service, Mr. Hurwitz discovered that a reduction in the geyser's water supply is causing the longer waits between eruptions. Their study, published in the journal Geology, found that the length of the intervals may be influenced by the amount of water that has seeped into the geyser's underground plumbing system.
The amount of water in the system depends on rainfall. As a press release from the USGS puts it:
Multi-year precipitation records also strongly correlate with geyser behavior. Based on these results, the study proposes that an extended drought should result in longer intervals between eruptions, and perhaps even cessation of activity in some geysers. In contrast, in years with high precipitation, eruption intervals should be more frequent.
Yellowstone National Park has been in the grips of an eight-year drought, with scientists and visitors reporting parched streams and lakes, withered plants, and declining populations of some animals. Climatologists warn that global warming is causing a profound shift in the climate of the American West, one that will leave it with reduced rainfall for decades.
The Caspar [Wyo.] Star-Tribune notes that, since 1959, three earthquakes have lengthened the intervals between Old Faithful's eruptions. Following a 1983 quake in Idaho, "that interval lengthened, steadily, to 80, 85 and, most recently, every 91 minutes, on average." But, as the San Jose Mercury-News points out, there were no major quakes during the time of Hurwitz's study.
Hurwitz told both papers that drier weather in Yellowstone will only lengthen the intervals.
"Our grandchildren will have to wait longer for Old Faithful to erupt," he told the Star-Tribune.
You can watch Old Faithful's eruptions from your computer via the National Park Service's live geysercam.