A group of skiers at the Vemdalen Ski Resort in Jämtland County, Sweden were treated to the stunning sight of a crisp sun halo appearing over the snowy mountain. Luckily, resort employee Håkan Hammar captured this very rare natural phenomenon so beautifully on video. According to Hammar, he’d never seen anything like it.
(translated) Was on the mountain… got up at the head and saw this phenomenon: Halo …. amazing. Never seen anything like it.
According to NASA APOD, the halos are caused by ice crystals refracting the light.
…there are actually millions of tiny lenses: ice crystals. Water may freeze in the atmosphere into small, flat, six-sided, ice crystals. As these crystals flutter to the ground, much time is spent with their faces flat and parallel to the ground. An observer may find themselves in the same plane as many of the falling ice crystals near sunrise or sunset. During this alignment, each crystal can act like a miniature lens, refracting sunlight into our view.
via NASA APOD