The waterfall Barnafoss is in River Skjalfandafljot near the abandoned farm Barnafell in Ljosavatn County. There the river runs in a narrow, and close to 100 m deep canyon. According to legends, young and brave men jumped across its narrowest parts. During prolonged subzero periods, the spray creates an ice arch across the river above the waterfall and sometimes a rope was strung across the river there to quicken this development. Flocks of sheep were driven over that bridge to graze on the Thingey Island between the two branches of the river.

In 1925, the housewife of Barnafell and her son slid helpless on the iced ground down the slope from the farm and hung on for dear life on the brink of the canyon just below the waterfall. The older son witnessed this and ran to bring together all the ropes he could find and tied them together. He then roped himself down to his mother and brother and rescued them. Two years later, he received an honorary acknowledgement from the Andrew Carnegie Fund.