On a lookout tower, 125 miles (200 kilometres) north of the Arctic Circle in Jak Territorial Park, Northwest Territories, Canada, the son of Roberta Unruh (Member 58,642) spotted a triplet of rainbows. All three colourful siblings were born of the union between sunlight and the rain shower from a Stratocumulus cloud. But with one of them, the sunlight took a rather different path. 

The bows to the left and right are your basic primary and secondary rainbows. They are produced by sunlight shining directly onto raindrops. Observers often consider it a treat to see both rainbows together, but this is actually quite common. The third rainbow is the special one in the family. Known as a reflection rainbow, it is at a different angle from the other two, and it touches the primary rainbow at ground level. This is something reflection bows always do. It is rare, and it tells us something about what was behind Roberta’s son’s back as he stood there in the lookout tower.

Just as its name suggests, this bow was formed by light that had been reflected. A lake behind the lookout tower reflected the sunlight up onto the rain shower. Since it shone onto it from a different angle, it produced a rainbow at a different angle – a surprise addition to the family that no one had been expecting.