These clouds occours when there is a lot of wind blowing above a mountain range. The get their colors from the ice particles in the clouds that reflects the sunlight in different colours.

On 19. December 2017 there where a lot of wind in my area. The Lyngen alps east of Tromsø city was probably the reason these clouds could appear on this day.

There is polar night in Tromsø, Norway from 27. November to 16. January. But it's not so bad when you get displays like this on daytime. Mind that this is taken around 10:30 and 11:00.

Watching the cloudscape change every second was cool too.

The clouds where the next day visible above Northern Sweden and we could see the bright sun reflection from these clouds.