Geology 36, 451–454 (2008)

The discharge rates of four geysers in North America's Yellowstone National Park — Old Faithful, Daisy, Aurum and Depression — reflect precipitation in the watershed of the Madison River. For decades geologists have tried to link geyser eruptions to external forces including atmospheric pressure and the tides, but until now had little success.

Shaul Hurwitz of the US Geological Survey in Menlo Park, California, and his team propose that years with lots of rain (or snow) result in higher than usual pressures in the 200 °C-plus underground reservoirs that feed geysers, shortening eruption cycles. Conversely, after snowmelt in spring, cold water percolates into geyser conduits and lowers their temperature, lengthening eruption intervals. The work is based on data recorded between 1998 and 2006 by temperature sensors in geyser outflow channels.