One day there was a beautiful light to be seen in the sky with wonderful colours. It was staying there for hours while it was freezing 20 degrees below zero! This photo is not special nice but it's going over what I saw. This shot was taken on januar 2005. Have seen it this year too but not so nice as that one. These rare clouds, sometimes called mother-of-pearl clouds, are 15 - 25km (9 -16 miles) high in the stratosphere and well above tropospheric clouds. They have iridescent colours but are higher and much rarer than ordinary iridescent clouds. They are seen mostly but not exclusively in polar regions and in winter at high latitudes, Scandinavia, Alaska, Northern Canada. Lower level iridescent clouds can be seen anywhere. Nacreous clouds shine brightly in high altitude sunlight up to two hours after ground level sunset or before dawn. Their unbelievably bright iridescent colours and slow movement relative to any lower clouds make them an unmistakable and unforgettable sight.