The Nor’ West arches always looks stunning in the evening, especially in Autumn and Winter when the colours really stand out during sunset. The Canterbury region of New Zealand is renknowned for Nor’ West arches in its skies due to the Southern mountain ranges (Southern Alps) which aid their formation.
This arch was caused by the strong Nor’Westerly winds which brought long, thin lenticular waves low across the horizon as a result of the obstruction of wind flow by the Southern Alps. An increase of higher level moisture resulted in the transition from altocumulus lenticularis to a straight arch, producing the effect shown in the photo.
What I loved most about this Nor’ West Arch was the contrast between the calm blue and almost menacing greyish purple, separated by a film of textured and undulated orange. This photo was taken looking North where the arch was most vivid at the time. The arch preceded a cold front which smothered most of the South Island.
For more information on these clouds visit Nor’ West Arch