Stacey Cougill's picture

How and why is this formed?

Observed: 20th November 2009 By: Stacey Cougill
unknown 1
unknown 2
Description:

This was seen in a hill range called the Fannichs, in a stream that flows into Loch Glascarnoch, about 20 miles from Ullapool. Does anyone know how or why it was formed?

Identifications
  • Pancake Ice
    Confidence: I'm as sure as I can be.
Species interactions

No interactions present.

Comments

Syrphus's picture

First, I don't think this has

First, I don't think this has anything to do with wildlife - at least not directly. I think you need a water chemist, and a physicist.

I don't recall ever seeing something quite like this, but similar things are not unusual in the Highlands. What follows is speculation.

The white foam is located in a small bay, where I suspect there is a slow eddy, isolating the foam in a slowly rotating mass. I usually see circular *raised* areas in that situation, like lumps of meringue. I suspect that the flat 'discs' are these lumps once collapsed.

Two questions remain - what forms the foam? And how do the circular masses form? On the first, I have always assumed that it comprises a cocktail of complex organic molecules (proteins, carbohydrates, etc.) from the surrounding peat. On the second, I have not a clue, but suspect that the answer lies in arcane physical chemistry interacting with the flow of the burn.

I can't point you to an appropriate expert, I'm afraid. I hope this find enhanced your trip to that superb range of hills.

TRY

recording wildlife with The Recorder's Year on www.hbrg.org.uk/TRY.html.

Tuisku's picture

Are the discs nearly frozen?

Very unscientific response to the formation of the discs: it looks quite cold there - I'd suspect that the discs are nearly frozen and as small particles get stuck in whirlpools, more and more particles join, and because it is cold, the stuff freezes and forms a disc.

Vinny's picture

Pancake Ice...

...is a North American term I recalled for this phenomenon. Checked it on Google and found this Wiki page:

http://en.wikipedia.org/wiki/Pancake_ice

Kind Regards

Vinny