Unusual Light Pillars Over Latvia

What's happening over that town? Close inspection shows these strange columns
of light occur over bright lights, and so likely involve falling ice crystals reflecting
back these lights. The reason why these pillars fan out at the top, however, is
currently unknown -- readers of APOD might help figure this out by participating
in an online discussion. The above image and several similar images were taken
with a standard digital camera in Sigulda, Latvia last month. The air was noted to
be quite cold and indeed filled with small ice crystals, just the type known to create
several awe-inspiring but well known sky phenomena such as light pillars, sun pillars,
sun dogs, and moon halos. The cold and snowy winter occurring this year in parts
of Earth's northern hemisphere is give sky enthusiasts new and typically unexpected
opportunities to see several of these unusual optical atmospheric phenomena for themselves.