[Inyo-Mono]

It wasn't that prompt. I think he died the next day, after around 20 hours of agony. His eyes went as white as two poached eggs. One of the people who pulled him out got serious burns.

Sounds like maybe you too have read the book Death in Yellowstone.

[Steely Tom]

I didn't read that, but I heard about the case on-line somewhere, and did about five minutes worth of research, and got what I think is more or less the whole story. His name was David Allen Kirwan. When people were yelling at him not to jump in, he yelled back something like "f*** that, I'm going in!"

Anyway, the internet continues to amaze me.