photo #4453483

On a morning hike with her family in the South Mountain Preserve in Phoenix, Arizona, US, Michele Boyle (Member 60,981) spotted this nearly colourless optical effect. It was in January, and Michele remarked that the air was full of moisture which seemed to rise off the desert floor. The fogbow was visible courtesy of the refraction, reflection and diffraction of the Sun’s light as it shone onto the tiny droplets of fog. Just like rainbows, fogbows appear ahead of the observer when direct sunlight is shining from behind. Morning sun shining onto fog that’s clearing away is an ideal setup for the ethereal arc of a fogbow to appear, as it means the fog droplets are particularly small and consistently sized. As the fog dissipates, look for your shadow which will point directly to the centre of the subtle, diffuse, often colourless bow