Rare pillar lights appear in Alberta skies
Alberta's freezing temperatures have been the dominant weather story for the region this winter, but a rare occurrence inspired some to venture outdoors in temperatures below minus 40oC to see this stunning atmospheric phenomenon.
On February 10, 2019 Dan Tanner posted this image of the rare pillar lights to Twitter, which show the special early morning light show in Blackfalds, Alberta.
These vertical beams are an optical illusion that appear when tiny ice crystals are suspended in the air near the ground and reflect light, such as sunlight, moonlight, or streetlights.
The flat edges of the small crystals acts as mirrors to reflect the light, and the resulting beams are the collective reflections, and are more pronounced when the ice crystals are larger in size.
Ice crystals require dense, cold air to form, and the recent conditions provided the perfect set up for this light show, as the coldest spot in Canada was Hendrickson Creek, Alberta, which reached minus 44°C on February 9, and most of the province remains in an extreme cold weather alert.
