Yellowstone National Park rangers suspended their search late Wednesday afternoon for an Oregon man who fell into a thermal spring at the Norris Geyser Basin on Tuesday afternoon, a park spokeswoman said.

Rangers found a few personal effects, but no remains were left to recover, park spokeswoman Charissa Reid said.

Rangers tried to reach the site but quit "due to the extreme nature and futility of it all," Reid said, referring to the high temperature and acidic nature of the spring.

Earlier Wednesday, Reid told K2 Radio, "The Norris Geyser Basin is one of the dynamic parts of the park."

It is the home of Steamboat Geyser, the largest geyser in the world. It's unpredictable, but its eruption is a big park event.

There are three basins in the area: Porcelain Basin, the 100 Springs Plain, and Back Basin where the fatality occurred at Pork Chop Geyser.

"We believe, geologically, it's one of the hottest, oldest, and one of the largest thermal areas in Yellowstone," Reid said.

That's awesome.

And it's dangerous:

  • A scientific borehole test found water at 459 degrees Fahrenheit. Water rarely dips below the boiling point.
  • A Ph ranging to that of battery acid.
  • The surface could be a thick rock or a thin crust covering very hot water.

These are among the hazards rescuers may deal with in trying to recover the body of Colin Scott, 23, of Portland, Ore., who walked about 225 yards away from the boardwalk and fell into a thermal hot spring.

Reid did not know exactly how rangers will conduct the recovery operation, she said. "Our biggest emphasis in anything like that is the safety of our staff."

Rescuers will need to traverse geyserite, the name of the white rock that forms when rhyolite -- a volcanic rock -- is dissolved and moves to the surface.

"It can be just a thin little skift, or it can be a very thick rock," Reid said. "It just depends on how much has built up over time."

"One of the reasons that it's illegal to walk in the thermal areas, besides the fact that you could injure the features themselves, is that there's not really any way to tell whether you're walking on firm ground or you're walking above boiling hot water and you're just going to break right through the crust," Reid said.

Note the word "illegal." A violation of park rules -- leaving a board walk, impaired driving, drug possession and so forth -- is a federal crime.

"The regulations here aren't arbitrary," Reid said. "They're in everyone's best interests."