‘Punch hole clouds’ extend east of Spokane to North Idaho

Dawn unveiled an unusual and beautiful cloud formation Wednesday that was last documented in the Inland Northwest five years ago.

A group of “punch hole clouds” formed to the east of Spokane just as the sun was rising. The formations extended across North Idaho.

National Weather Service forecasters immediately spotted them and photographed the dramatic cloud formation.

The holes appeared in a fine layer of clouds hovering around 20,000 feet above ground. Jet aircraft traveling from northwest to southeast at around 35,000 feet left a trail of ice crystals from their exhaust, forecaster Ron Miller said.

Ice crystals can also form from sudden pressure changes caused by the airplanes’ wings.

Those ice crystals drifted down in the relatively stable air mass, passing through the clouds, which are composed of water droplets. The water droplets adhered to the ice crystals, creating a darker visual appearance at the center of the elongated holes.

Miller said the holes appeared as streaks, extending from about Coeur d’Alene to Lookout Pass.

In one photo, an exhaust trail from a subsequent jet can be seen through the hole.

The last time such clouds were seen in the Inland Northwest was in 2010, Miller said.

One weather service forecaster noted that many of his colleagues had never seen this phenomenon in person.

Visual-light satellite images from space confirmed that three to four of the streaky holes were evident Wednesday morning, Miller said. The clouds eventually changed shape and drifted to the southeast.