A scene captured 30 minutes before sunset by Geir Øye (site & more images) at Ørsta, Norway on 20th February, 2008.

Geir had only a three minute window of gaps in the lower cloud and so had no chance to observe closer to and after sunset. Nacreous or lower lenticular? We cannot be absolutely sure, there is much other iridescence in the sky and the stratosphere temperature went down to -80C that day, low enough for PSC formation. Whatever they are, a scene of breathtaking beauty.

Image ©Geir Øye, shown with permission.