Noctilucent clouds in motion

On the night of June 21, 2016, photographer Derek Mellott from the town of Gibbons, Alberta, Canada recorded this fantastic display of noctilucent clouds (NLCs).

"They were the brightest I have ever seen," he said. "It seemed like a good time to record a time lapse." 

Video courtesy Derek Mellott

NLCs are not fully understood and are a recently-discovered meteorological phenomenon; there is no record of their observation before 1885.

They are most commonly observed in the summer months at latitudes between 50° and 70° north and south of the equator. NLCs used to be confined to Polar latitudes but have recently started brightening and spreading towards the equator. Their occurrence is also increasing in frequency.

They can form only under very restrictive conditions and their occurrence can be used as a sensitive guide to changes in the upper atmosphere.

Featured image credit: Derek Mellott