Why Was Christmas So Cold This Year?

By Rafi Letzter

It was a frigid Christmas in much of the United States.

Chicago and Minneapolis both experienced their coldest December 25ths in decades. Erie, Pennsylvania weathered a stunning lake-effect storm that dumped more than 4 feet (1.2 meters) of snow on the city, shattering state records and prompting the local government to declare a snow emergency. And both Portland, Oregon and Seattle had a rare white Christmas.

The below-average temperatures are the result of a mass of Arctic air "buckling" southward from northern Canada toward the eastern U.S., said Robert Oravec, a lead forecaster at the National Weather Service's Weather Prediction Center.

"This weather pattern is not unusual or unseasonable," Oravec told Live Science.

The buckling air mass is the kind of thing forecasters expect to see a few times in a given winter , Oravec said. Though expected, the air mass can still result in weather far colder than usual for a given time period.

The current Arctic chill should remain in place for "at least another few days," he said.

Forecasters expect very cold weather and biting winds to persist across the northern Plains, the Great Lakes region, and cities along the east coast for much of the next week. Ovarec said that he expects to see