The great snowstorm caused extreme temperatures in the northwestern United States.
David Ryder / Getty Images
From icy winds close to minus 60 degrees in the Upper Midwest to an ice storm that can reach the Gulf Coast, it is rare that winter weather is so extreme.
The cause is that a polar vortex forms a very active jet stream.
That means cold, snow and ice for hundreds of millions of Americans.
On Saturday, more than two-thirds of the nation was under some kind of winter weather alert. ranging from freezing wind warnings for the northern plains to winter storm warnings for the Pacific Northwest. There were also winter weather advisories in South Texas and ice storm advisories in the mid-Atlantic, reported CBS News.
A few weeks ago, the polar vortex, which is normally located near the North Pole, broke into pieces, a natural occurrence that occurs every two winters. Smaller vortices spread across the northern hemisphere, bringing pockets of arctic air to Siberia, Europe, and North America.
For Sunday and Monday, the icy air currently over the northern plains will sink into central Texas, Bringing freezing winds below zero.
The image below traces the origin of cold air from the Arctic Ocean, down through Canada and south across the US plains.
In case anyone was wondering where the cold air was coming from…..the Arctic.
The Arctic is bringing the cold air. pic.twitter.com/Xu6cjDXUEh
— Zach Covey (@ZachCoveyTV) February 12, 2021
The temperatures will be dangerous. On Sunday morning in North Dakota, Minnesota and Wisconsin, wind chills will bottom out in the -40 to -60 degree Fahrenheit range.
Over 100 million Americans will be impacted by a coast-to-coast winter storm that will deepen in the Southern Plains tomorrow and lift into the MS/TN/OH Valleys and Northeast through Tuesday. In addition, bitterly cold temperatures will lead to dangerous wind chills.
Stay safe! pic.twitter.com/N1kNKGqNKu
— NWS Weather Prediction Center (@NWSWPC) February 13, 2021
The lows will fall below zero from Saturday through Tuesday morning in Kansas City, possibly dropping to -15 on Monday or Tuesday morning. Taking the wind into account, temperatures will range from 20-30 below freezing on Sunday, Monday and Tuesday morning.
Even Dallas, Texas, will experience temperatures well below freezing on Monday and Tuesday mornings. Actual temperatures will be 50 degrees below normal Monday morning in much of Texas and Oklahoma.
Heavy snow is falling across the mountains and lowlands of Washington and Oregon today with significant icing in northwest Oregon. Significant icing will also occur over Virginia and southern Maryland into Sunday. pic.twitter.com/BmE6lolfGH
– National Weather Service (@NWS) February 13, 2021
Despite being extreme, the weather is not as extreme as it could be. Over the past few decades, due to man-made climate change, colder extremes are becoming less extreme. As an example, In Minneapolis, the coldest day of each year is now 12 degrees warmer than it used to be.