Rare Kelvin Helmholtz clouds, known as “wave clouds” in Icelandic, caught the attention of Reykjavík residents yesterday, RÚV reports. Meteorologist Birta Líf Kristinsdóttir says such clouds are very rare and are formed by strong winds.
“They form in unstable air where the wind speed changes rather quickly with altitude and are not a common sight here in the country. That is similar to what happens when waves form in the ocean, and there are two fluids with different densities moving at different speeds,” she stated.
The same cloud formations were seen at Skaftafell in South Iceland in 2015.