On Saturday, early-morning Stockholmers who could see a so-called vertical column that arose through a combination of the right kind of ice crystals that are right in the atmosphere and a low-lying sun.
– It is a phenomenon under the umbrella term halo phenomenon and is light that is refracted and reflected in ice crystals. In this particular case, it is sunlight that is only reflected in a certain type of ice crystals, explains Linus Karlsson, meteorologist at SMHI.
Hard to predict
Similar phenomena can occur over streetlights on cold evenings and nights when the sky can become completely streaked with shining pillars.
– Pillar of light is usually the term used when it comes to a more artificial light source.
The phenomenon is volatile and difficult to predict. There are many parameters that come into play, but one that is more predictable is the cold.
– We are in a situation where it is very cold, which is quite favorable conditions for having ice crystals at several levels in the atmosphere. Then there are usually reports that vertical pillars have been seen somewhere in the country, says Linus Karlsson.