The sparkling trout stream known as Mammoth Creek begins cold and full of life… until it reaches live volcanic vents near the Long Valley Caldera and becomes a dangerous, yet beautiful landscape of sky-blue boiling pools, steaming shorelines, and bubbling cauldrons of hydrodynamic power.
The Hot Creek Geologic Site is managed by the U.S. Forest Service and monitored by the U.S. Geological Survey and in addition to being gorgeous, it acts as an important fault activity indicator. Part of the Long Valley Caldera, the creek is icy with snowmelt until it reaches upwelling springs of water heated by the Inyo Dome magma some ten miles away. This water, which reaches temperatures as high as 430 degrees Fahrenheit deep underground (where the pressure keeps it liquid) eventually percolates up in numerous locations along the stream and elsewhere, raising the temperature dramatically.
Once a site that allowed swimming in roped off areas (with prominent signs notifying the swimmers of the 14 deaths caused by the pools over the past few years), Hot Creek Geological Site no longer allows human contact with the water; back in 2006, the pools began to occasionally “geyser” and the main spring experienced temperature surges. Closed in June 2006, the former swimming area once held a wooden bridge and walkway that gave visitors a good view of the “Cauldron,” a bubbling outpouring of deep water that visibly causes the surface to dance and burble. A good shove was all that was needed for a swimmer to float on the surface of the Cauldron, where the water’s force was strong enough to make one bob like a cork in a glass of champagne.
Visitors can still get a number of fine views from the top of the parking lot, and can still take the original walkway down to the water. Entering the water, however, is suicidal; hence the fence that blocks direct access for the unwary and incautious. But even though swimming is now verboten, Hot Creek Geologic Site is still well worth the trip.