Rarely seen cloud formations

There seems to be no end to strange cloud formations! From Punch hole clouds to cloud vortices, enjoy these rarely seen cloud formations!

Punch Hole Clouds may appear as a circular or oval holes in a layer of supercooled clouds; sometimes they assume a form of a perfect circle and persist for quite a long time, drifting together with the cloud layer. One explanation seems to blame the air traffic (the jet contrail intersections) combined with a thermal inversion (a circular motion of a rising warm air). Here is one, observed over the Gunnison Valley in Colorado

Another strange hole in the cloud, reported from Mobile, Alabama USA, Dec. 2003 (and covered by BBC News):

                          Another cloud "wave", similar to the one over South Dakota Badlands

                                  Roll clouds... get into a small plane and start "surfing" them! 

        More Incredible and Fascinating Clouds

     ...that make our sky worthy to look at from time to time (those who only look at the computer monitor, take                note). Here is an extremely strong thunderstorm cloud that brewed over northwest Calgary