It’s that time of the year again, or rather the temperature is that low again. Strange pillars of light in the sky? Ice pillars, or light pillars, form under conditions of very cold temperatures.
They are caused by light being reflected by crystals in the atmosphere, and careful observation of them can actually provide some insights about the weather. The source of the reflected light can be anything from the sun to streetlights. Color will vary depending on the light source.
Since these require very dense, cold air, with many ice crystals, they are common in polar regions.
Trego's Mountain Ear 