Friday, February 26, 2010

Friday photo

Firehole River, Yellowstone National Park. January 2005.

More peculiar ice formations. My best guess here is that the snow and ice accumulated at the end of the branches while the surface of the river was thinly frozen; then perhaps there was just enough melting to allow the river ice to break up and remove the foundation that these shapes had been built upon. For that to work, I think the surface of the ice would have to have been covered with snow, so that these formations didn't directly attach to the river ice itself (as they don't appear to be broken). Does that make sense?


Heather said...

Wow, that's beautiful (and strange-looking). I don't remember ever seeing anything like that -- the conditions must have to be just right?

Cranberry Necklace said...

My read is that the river is usually too warm to freeze. However, in a very cold spell, the stiller, cooler eddies just downstream of the trees in the river were cold enough to freeze, then collected snow on the ice. The warm river washed away any other remaining ice, leaving these discs of snow-covered ice bound to the trees in the river.

Scott Hanley said...

That's a good point. This is the Firehole, which has a hard time freezing in the geyser basin, but this shot is slightly upstream yet of the geyser runoff. I hadn't been thinking in terms of only the stiller portions being able to acquire ice, but that seems quite likely. It would also make more plausible the removal of ice without enough violence to break up these formations.