Sometimes the most memorable sight on a mountain is above the mountains. In late November 2019, Michael Schneider photographed an elaborate display of rings and bright arcs around the Sun near Arosa, Switzerland. The result looks wonderfully improbable, yet the ingredients were light and tiny ice crystals.

The photographs are a lovely reminder to leave a little space for the unexpected. A ski outing provided the setting; a pause to look at the sky provided the story.

Bright ice halos and arcs around the Sun above skiers at Arosa
Bright ice halos and arcs around the Sun above skiers at Arosa. Gallery attribution: Michael Schneider.

Where the photographs came from

In his account of the event, Schneider places the scene on the Hörnligrat above Arosa. He was waiting to meet a friend and experimenting with a new smartphone camera as the sunlight changed. His post dates from December 2019, with later updates following the photograph’s wider circulation.

This gives the gallery a place, a maker and a time. The pictures should not be presented as a new event every time someone discovers them online.

How ice makes a halo

Halos form when light interacts with ice crystals in the atmosphere. Crystal shape and orientation influence the pattern we see. A familiar example is the 22-degree halo, a ring whose radius is an angle in the sky—not a distance you could measure in kilometres from the observer.

An annotated version of Michael Schneider’s Arosa halo photograph
An annotated version of Michael Schneider’s Arosa halo photograph. Gallery attribution: Michael Schneider.

Different effects can appear together, which is why an annotated image may contain several names. The Atmospheric Optics halo collection is useful for comparing forms rather than calling every bright arc a rainbow. Rainbows and ice halos arise from different optical circumstances.

Look at the whole scene

Begin with the horizon. Then follow the visible curves, noting which features form a complete ring and which appear as separate arcs or bright spots. A wider view often makes the arrangement easier to understand than a tightly cropped photograph of the brightest patch.

Keep ordinary sun safety in mind: do not stare at the Sun, and do not point an optical viewfinder or binoculars at it. You can enjoy the surrounding sky while using a building or another solid object to block the solar disc from view.

Can you plan a trip around a halo?

You can plan a mountain day, but you cannot reserve the necessary crystals, light and viewing angle. Choose Arosa for the activities and scenery you would enjoy anyway. Treat an unusual sky as an extra, rather than the only measure of a successful outing.

Winter photographs become even more rewarding when their context is clear. Our look back at Newfoundland’s 2020 blizzard explores another spectacular set of images and the everyday circumstances behind them.