The polar vortex returns to North America
The infamous “polar vortex” made a return to North America last week. Temperatures plunged to as low as minus 50 degrees across the northern U.S. that led to several states of emergencies. Thousands of flights were canceled, and people were warned to stay inside to avoid instant frostbite.
One of our weather and commodity clients near the Canadian border reported a low of minus 56 degrees last week. Wind chill tempera-tures in North Dakota have been down to near minus 60 degrees. In Chicago, the Windy City, a low of minus 21 degrees was reported with a wind chill temperature of close to minus 40 degrees. The frigid temperature was just 6 degrees short of its all-time low temperature of minus 27 degrees.
It was so cold in the Chicago area that residents were hearing “frost quakes.” Also known as “cryoseisms,” water expands underground when it freezes very quickly. The fast expansion can stress the soil and split rocks resulting in loud booms. It’s a phenomenon that is relatively rare.
Many of us have heard about this polar vortex. It started to become more familiar during the 2014 North American cold wave as extreme frigid temperatures were affecting parts of Canada, the north-central and upper eastern portions of the U.S. during an extended period through the late winter months of the 2013-14 season. Record lows were felt in those areas well into March of 2014.
This same polar vortex also brought our region the unbelievably frigid temperatures in January of 2014. From the 1st through the 17th, Coeur d’Alene’s high temperature was below the freezing mark. During that time, the normal high temperature during that time was only 25 degrees, or 11 degrees below normal. The average low at Cliff’s station then was only 12 degrees.
The most intense coldwave in North Idaho’s history that was likely caused by a polar vortex occurred in late January and early February in 1950. Records lows were reported that still stand today.
On Feb. 28, it was minus 21 degrees in Coeur d’Alene. The mercury went down to minus 28 degrees at a station northeast of Sandpoint. The most frigid day was Jan. 30, 1950, when Coeur d’Alene reported its all-time record low of minus 30 degrees. On that date, Post Falls went down to minus 31 degrees and Sandpoint reported a low of minus 38 degrees. Record lows in the minus 20s were reported in the lower elevations through Feb. 3, 1950 before recovering.
Most of the time, when the polar vortex moves southward, the strongest portions are near Baffin Island, Canada, an area just southwest of Greenland, and northeastern Siberia. Also, the Cascade and Rocky Mountains often protect the West from these intense Arctic blasts as most of them go to the east over the central portions of the country. However, there are occasions when there is an intense Arctic outbreak over the northern portions of the western U.S. and southwestern Canada like in 1950 and 2014.
The polar vortex is a relatively large upper-level low pressure system consisting of large masses of cold, dense Arctic air that is located near the North Pole. There’s also a polar vortex at the South Pole. When the polar vortex is strong, the frigid cold air mass will often stay confined near the North Pole as the jet stream increases in strength. But, when the vortex weakens and splits into two or more vortices, like what occurred last week, the cold air will often push southward into North America, Europe and Asia.
As some of that cold air to the east moves west, we will see some very cold weather here in North Idaho. However, the air mass would not be nearly as cold as the one last week over the center of the country.
Thanks to the warmer Pacific Ocean, temperatures last month across North Idaho were milder than normal. Our coldest day in Coeur d’Alene in January was 18 degrees on the 30th. By contrast, we had a high of 47 degrees on the 4th.
January’s precipitation total for Coeur d’Alene ended up at 3.21 inches, a little below the average of 3.77 inches of rain and melted snow. Speaking of snow, Cliff measured 14.8 inches last month, which is below the normal of 21.4 inches.
For February and March, we still see about another 20 inches of snow for Coeur d’Alene. February of 2018 was our snowiest month and it’s quite possible that February of 2019 will also be our snowiest month as storms will be coming from the colder northwestern regions rather than from the south.
We should see some snow toward the end of this week with a good chance of snow next week as a series of storms are expected to move through the area. February should also be colder as well.
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Contact Randy Mann at randy@longrangeweather.com