Extreme cold whipped Ontario and much of the northeast on Friday and Saturday, but a lucky few of those willing to brave temperatures colder than -30 C over the weekend were treated to some views of a spectacular seasonal phenomenon known as light pillars.

During extreme cold snaps, this atmospheric optical phenomenon forms vertical beams of light that travel up from their sources and reflect through ice crystals suspended in the ultra-cold air.

On cold and calm nights, these tiny floating ice crystals act as miniature hexagonal-shaped mirrors concentrated in the millions, which reflect light upwards to form searchlight-like beams that project high into the sky.

Light pillars were spotted around Ontario over the weekend, including several reports out of Ingersoll, where temperatures plummeted to the minus double digits.

Light pillars tonight in Ingersoll, ON. -14°C (-20°C with windchill) #ONStorm pic.twitter.com/ZhkdpCC7Hy

— Halo Dudette (@halodudette) February 4, 2023

Multiple views out of Ingersoll confirm that this phenomenon was widespread in the town of roughly 13,000.

STUNNING light pillars around 10PM in Ingersoll! They have since diminished but I will be checking again later tonight! You don't get to see this very often here! #ONwx #lightpillars #meteorology @isabel_ONwx @southernon_wx @cluke5 @StormhunterTWN @weathernetwork @jasonoyoung pic.twitter.com/anfGQeqWCr

— David Piano (@ONwxchaser) February 4, 2023

A video of the light pillars rising against a residential neighbourhood with falling snow has an almost apocalyptic vibe to it.

Pillars of light in Ingersoll, Ontario, #Canada. February 04, 2023 pic.twitter.com/O70Z03yYLI

— Себастьян Перейро 🦋🇺🇦 (@stringerukraine) February 5, 2023

Similar conditions allowed light pillars to form about 130 kilometres away, in Shelburne, where temperatures dipped to -25 C over the weekend.

It’s -25° near Shelburne, Ontario and there’s lots of pretty light pillars. #ONstorm #weather @weathernetwork pic.twitter.com/aMUBmDzeOu

— Bryan (@BEMcGowanPhotog) February 4, 2023

Light pillars were spotted elsewhere in southwestern Ontario amid polar temperatures.

Great (cold/crystaly) conditions for light pillars tonight ✨ pic.twitter.com/g8BHHtzOVK

— Marianne Braca (@Braca_M) February 4, 2023

This is not the first time in recent years that the phenomenon has appeared over southern Ontario skies. One year earlier, light pillars were spotted in the Greater Toronto Area during an extreme cold snap.