A rare cloud formations seen over Anacortes and Ferndale caused a stir Monday afternoon. At least two punch-hole clouds appeared and made an eerie site. The weird formation usually happens when a plane either ascends or descends through a super-cold altocumulus cloud. According to Weather.com studies have shown... ...that aircraft passing through these cloud layers can trigger the formation of the heavier ice crystals, which fall to Earth and then leave the circular void in the blanket of clouds. [Researchers] concluded that aircraft propellers and wings cause the formation of those initial ice crystals. There are zones of locally low pressure along the wing and propeller tips which allow the air to expand and cool well below the original temperature of the cloud layer, forming ice crystals. People often mistake the clouds for UFO's. Brandon Blake sent in several photos. He said the clouds disappeared pretty quickly. Then said, "But thank you for the info. I can ease my bosses fears of an alien mother ship. Or not. I think I'll just let him keep thinking that.

Source: A punch-hole cloud photographed near Anacortes, Washington (Photo: Robert Bruckner) Story: KOMO News Staff

A rare cloud formations seen over Anacortes and Ferndale caused a stir Monday afternoon. At least two punch-hole clouds appeared and made an eerie site. The weird formation usually happens when a plane either ascends or descends through a super-cold altocumulus cloud. According to Weather.com studies have shown... ...that aircraft passing through these cloud layers can trigger the formation of the heavier ice crystals, which fall to Earth and then leave the circular void in the blanket of clouds. [Researchers] concluded that aircraft propellers and wings cause the formation of those initial ice crystals. There are zones of locally low pressure along the wing and propeller tips which allow the air to expand and cool well below the original temperature of the cloud layer, forming ice crystals. People often mistake the clouds for UFO's. Brandon Blake sent in several photos. He said the clouds disappeared pretty quickly. Then said, "But thank you for the info. I can ease my bosses fears of an alien mother ship. Or not. I think I'll just let him keep thinking that.

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