Stacey Cougill's picture

How and why is this formed?

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

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?

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

No interactions present.


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.


recording wildlife with The Recorder's Year on

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

Kind Regards