Arctic blast swoops through Montana

What was going on last week with that crazy cold weather? Was it an Alberta Clipper, Bomb Cyclone, Winter Storm Elliot?

A record low temperature on December 22 of -48 degrees in Potomac and the third coldest day since 1959 recorded at Lindbergh Lake had people scrambling for extra layers, more firewood and wondering how the outside animals could handle it.

Satellite reports from the National Weather Service (NWS) showed -53 over the ponds along Hwy 200 east of Ovando.

"December 22 was -35 at the weather station near Lindbergh Lake," said Marty Kux, volunteer weather observer with the National Weather Service. "Previous lows were -40 February 3, 1989 and -37 December 29, 1990. It was the third coldest day recorded here since 1981."

"The cold weather was born in the region of Siberia the second week of December. Temperatures of -77 were recorded in Siberia," said Bob Nester, Senior Meteorologist Missoula NWS. "This weather was a unique cold air event, a novelty. It was extraordinary how the cold developed."

A high pressure ridge between Alaska and Russia funneled the Siberian cold air through Alaska and the Northern Territories and down the Rockies through Montana.

"The terms Alberta Clipper, Bomb Cyclone, and named winter storms are not from the Weather Service," said Nester. "The news outlets came up with those names."

Cold air is heavier and often pushed low in the atmosphere. Low pressure west of the Rockies sucked  cold air from the arctic air mass over the mountains and through passes like Roger's Pass, creating the east wind carrying the arctic air, explained Nester.

"Here on the ranch in Helmville, we were very glad this weather came before calving season," said John Pocha, Helmville.