Sun Dogs, Pillars & Mirrors: Optical Phenomena of the Subarctic Sky

What causes them

When the air is cold enough, tiny hexagonal ice crystals float in the atmosphere and bend sunlight in predictable ways, much like tiny prisms and mirrors. Depending on how the crystals are shaped and oriented, that bending produces halos, bright spots, arcs, and columns of light around the sun (or even the moon).

Sun dogs and halos

The most common sight is a pair of bright, often rainbow-tinged spots flanking the sun at the same height — the “sun dogs” (technically parhelia). They frequently appear alongside a 22-degree halo, a luminous ring encircling the sun. Both are best seen when the sun is low and the air is full of ice crystals.

Sun pillars and light columns

On very cold mornings and evenings, you may see a sun pillar — a vertical shaft of light rising from the sun as flat ice crystals reflect its glow. In town, the same effect can create eerie light pillars above streetlights, a purely local Yukon winter spectacle.

When and where to look

These phenomena favour clear, extremely cold days when ice crystals hang in the air, so deep winter is prime time. Look toward the low sun (never directly at it — shield it with your hand or an object), and scan for halos, flanking spots, and vertical columns. Around towns, glance up on frigid nights for streetlight pillars.

Capturing them

A wide lens helps fit a full halo in frame; block the sun itself behind an object to reduce glare and reveal the surrounding effects. As with all winter photography, keep batteries warm and be quick, since the crystals — and the display — can shift within minutes.

While the aurora dances at night, the daytime sky has its own quiet magic. Learn to spot sun dogs, halos, and pillars, and even an ordinary walk on a cold Yukon morning becomes a little astronomical event.

Frequently asked questions

Where to stay

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