Light pillars over northern Sweden
EarthSky Facebook friend Birgit Bodén shared this photo. It’s a sign of wintry weather already appearing at far northern latitudes. These streaks in the sky are called light pillars. They form when sunlight (or another bright light source, such as the sun) reflects off the surfaces of millions of falling ice crystals associated with thin, high-level clouds, for example, cirrostratus clouds. The ice crystals have roughly horizontal faces. They are falling through Earth’s atmosphere, rocking slightly from side to side.
Light pillars can be seen at any time of night when sky conditions are just right.
Thank you, Birgit!