Long Valley Observations for 2021 April 17

Passing through Long Valley, Calif., so Suzanne and I had to visit Hot Creek. My last visit there was thirty-five years ago, so things have changed. We spent a bit more than an hour there.

The walkways and access is now completely different. Back then, there were trails down near the creek next to the erupting features, and a bridge across the creek. Swimming was also permitted back then. This time the area is fenced off, and signs on the road announced that the area was closed at night.

The previous visit, all the activity was on the south bank of the creek. One of the craters was erupting as much as seven or eight meters high, and there were several other hot pools near it. Those craters are now all dead, with the geyser showing greenish water well below the rim.

In line with those craters, on the north bank was where there was activity, There are three pools that were not there during the previous visit, two of them hot and blue. They appear to be on a linear trend line from the old activity. The water levels of the blue pools were different, with the higher pool, about a quarter to half meter higher. It was continuously pouring water into the lower pool, and all three were pouring that water into the creek. We saw no change in the flow during our visit, although one time, due to the way the runoff can be hidden by the surrounding ground, I thought it had quit because I couldn't hear the runoff.

There were also at least two areas that appeared to be convection in the creek itself. Again, didn't notice any change in the brief time of our visit.

On the way out, stopped at the Casa Diablo powerplant. It too is changed, not surprisingly. The old US-395 road is now blocked off, and where the old hot ground and steam vents were on the northeast side of the road is now occupied by a generator complex. There's no good views of the area. Within the fenced in area, near where the old Casa Diablo Geyser used to be was something steaming heavily. This activity seemed to vary, but again, fences prevented any good views. There is still one area of thermally altered ground open to the west of the complex.