They witnessed a rare optical phenomenon called the "halo effect," which can be seen only in clear frosty weather.
"It is about —23-25 C in the Urals. There were small hexagonal ice crystals that cannot be seen with the naked eye in the air. The light interacts with ice crystals and, as a result, this creates the optical effect of the halo," explained Galina Sheporenko, a senior forecaster at the Urals weather bureau.
According to Sheporenko, the halo effect can only be seen a few times during the winter months and it is impossible to forecast exactly when it will happen.
"The halo effect can look different — wide variety of colored or white rings, arcs and spots in the sky," added Sheropenko.
Russians posted photos of halo effect in the Ural Mountains on the border of Europe and Asia.
