A hiker captured the incredibly rare phenomenon of an 'ice pancake' on a mountain walk in the Scottish Highlands.
Dan Brown was hiking up a Munro near Loch Fyne with his father when they came across the rare sight. Dan said: "Neither of us had ever seen anything like it, a perfect circle of ice slowly rotating in the water, so we thought it must be a rare occurrence and took some photographs.
'We assumed at the time that it was caused by the flow of the waterfall meeting the current of the stream, it wasn't until afterwards I read about ice disks and realised this was what we'd witnessed."
So, how do ice pancakes form? The answer is in one of two distinct ways, both of which require very specific conditions. In oceans, seas and lakes, ice pancakes form when waves cause forming pieces of ice to knock against each other, rounding their edges as they freeze and grow.
'Small rims are created on the edges as the knocking causes splashing water to freeze and join the rim,' the Met Office explained.
Alternatively, ice pancakes can form when foam on a river begins to freeze. The foam joins together, and as it is sucked into an eddy, a circular shape begins to form. 'As other bits of frozen foam and ice hit the forming disc they freeze to it and increase its size,' the Met Office added.
While ice pancakes often look like solid discs, they are usually quite slushy and easily break apart when lifted up.
'However, when given the conditions to consolidate, ice pancakes can end up binding with each other to form sheet ice and in rougher conditions waves can move these sheets of ice causing them to bend and crack to create ice ridges,' the Met Office concluded.
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