The Worm: Strange clouds hover like a mothership

Cloud creations: Late last month, an unusual cloud formation south of Wenatchee caught the attention of Wenatchee Valley resident Howard Lowell. He took some pictures and sent then off to the National Weather Service, which posted them on the agency’s Web site.

What appears to be holes or large openings in the cloud cover were an unusual phenomenon unofficially called “hole punch clouds.” (Google it. There lots of interesting information and pictures online about them.)

According to the weather service, the exact cause of the cloud formations is not known. But the theory is that descending air or airplanes traveling through the clouds disrupt the cloud cover. They occur in clouds that are composed of both ice crystals and super-cooled water droplets — water that is below freezing temperature but still in liquid form. Only slight disruptions in the clouds can create a void that gives the striking appearance of a hole in the clouds.

Continued with pictures: http://www.wenatcheeworld.com/news/2010/mar/15/the-worm-strange-clouds-hover-like-a-mothership/