For Frank:
I did put my fingers (cautiously) in 2 thermal pools. The temps seemed to be in line with a sauna at Disney World. 105/110 degrees. I did put the back of my hand on the ground in the viscinity of fumurals. The ground was bloody hot. I did not get burned, but "John, no more playing around".
I believe at Yellowstone's elevation, water starts boiling around 200 degrees.
There are somwhere in the vincinity of 250 geysers in the park. They talked about super heated. Sorry ! ! ! I never asked what that meant. I blew this one, because on our trip I constantly asked 'WHY or what does that MEAN'.
We were told to stay on the boardwalks (ecology and safety) and never, never be downwind, off a boardwalk, when a geyser erupts in the near vicinity. The person who told us was not official, but appeared to know his stuff. There was a possibilty of being scalded. That would be real NASTY ! ! !
john