On Saturday, Nov. 1, WCCO-TV viewers in the Twin Cities metro, and all the way to the extreme southeast in Houston, Minnesota, spotted a rare and mesmerizing sight, the hole punch or fallstreak cloud.

(credit: Rafe Nolte)

(credit: Rafe Nolte)

As mentioned in my blog below, the hole punch cloud formation is initiated by aircraft. Last year, also on a November day, hole punch clouds decorated the Minnesota sky. Atmospheric conditions are favorable this time of year, as air temperatures through which the aircraft pass must be colder than -20° and high moisture content must be present as well.

(credit: Darin Paulsen of Houston, Minn.)

(credit: Darin Paulsen)

For more on the science behind hole punch clouds, read on.

(credit: Hiromi Yokoi in South St. Paul)

(credit: Hiromi Yokoi)

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