A hiker captured the incredibly rare phenomenon of an ice disk on a mountain walk in the Scottish Highlands. The circular sheet of ice is seen in a glen on the mountain of Beinn Bhuidhe, which is south of Lochan Shira, and north of Achadunan. David Brown, 32, from Dunoon was hiking up the Munro when he came across the rare sight with his father. He said: "I was hiking Beinn Bhuidhe, a Munro at the head of Loch Fyne, with my father. "We’d taken mountain bikes with us and, for the best part, had been carrying them up a hydro track. "Visibility wasn’t great, but after about an hour-and-a-half the snow stopped and cloud cover started to clear. "We took a break to fill our water bottles from the burn by the track - that’s when we noticed the ice disk slowly spinning at the foot of a small waterfall." Both David and his father had never seen or experienced an ice disk in the flesh and were taken aback. He added: "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 and videos. "We assumed at the time that it was caused by the flow of the waterfall meeting the current of the burn, it wasn’t until afterwards I read about ice disks and realised this was what we’d witnessed. "We hadn’t encountered anyone else on the hike, it felt like we were the only people for miles around. "So then to happen across something so serene and perfectly formed, it felt surreal." The Met Office lists ice disks as "A rare phenomenon that tend to occur in very cold oceans and lakes. "They are most frequently seen in the Baltic Sea and around Antarctica but also form relatively frequently on the Great Lakes of the United States and Canada." The video was filmed on January 2.