The last two weeks has been interesting to watch, though the growth and extent of the ice is fairly normal. Here are the extent maps from December 12 (to the left) and December 27 (to the right).
As Hudson Bay and the Bering Strait have frozen up, most of the growth in ice from now on has little to do with the Arctic. You could almost call it cosmetic. It will be occurring in the Pacific, or the mouth of the Saint Lawrence River, or the Baltic Sea, and therefore will be fleeting, and have little to do with the Arctic Sea itself, which is what all the fuss is about in the summer.
I tend to watch the arctic ice-thickness maps, which can give you an idea where the ice is moving. It moves far more than many imagine. For example, hundreds of square miles of thicker ice that had been lodged north of Franz Josef Land was shifted west by storms and crashed into the north coast of Svalbard, over the past month. This created a sort of polynya of open water where the ice had been by Franz Josef Land, which swiftly froze over and became thin ice.
If this large body of ice continued to move west it might be flushed south through Fram Strait, which could create a situation much like occurred in 2007, when the thick ice was flushed south of the Pole, leaving the Pole with a thin skim of ice as summer approached, and, because the thin ice melted easily, the people who assume the icecap is in a “Death Spiral” had something to hype. (The main difference between now and 2007 is that there is much more thick ice north of Canada now.)
Watching the thickness maps allows you to see where the ice is piling up and where it is thinning, and gives you a rough idea on the total volume of ice up there. There are many interesting processes occurring that you seldom read about. For example, the same strong winds that blew the ice away from Franz Josef Land also blew the ice away from the south coast of the Kara Sea, and you can see that ice as thin blue lines of thicker ice now out in the middle of the Kara Sea.
Ice really piles up on the west coast of Baffin Bay, and grinds southeast along that coast and then along the coast of Labrador towards the North Atlantic. Ice also can pile up on the south and east coast of Hudson Bay, while the north coast can see polnyas form, so that even though the north was the first to freeze and the south was the last to freeze, by spring the south has thicker ice than the north. Lastly, ice can be seen piling up just west of the Bering Strait on the north coast of Russia; last year this ice was piled up 20 feet thick there by spring.
Watching the thickness maps brings many surprises, especially when storms wrack the ice. In the dead of winter, with temperatures at -40°, I have seen leads of open water form that are scores of miles across and hundreds of miles across. The open water freezes to thin ice almost immediately, but sometimes you can still see signs of that thinner ice months later. In a similar manner storms had a lot to do with the build up of thicker ice north of Canada.
At times the thick ice can crumble and be spread out into open waters, and mess up all sorts of neat calculations in the process. Where a cold current often sinks when it meets a warmer current, and more saline waters want to sink beneath more brackish waters, it is physically impossible for the ice to sink, and it bobs merrily onwards on top, often significantly chilling both the temperatures of the surface waters and the air, until it melts away. Therefore a strong wind transporting ice south can alter temperature maps with startling speed.
I imagine there are times when such alterations make a difference in the forecasts generated by computer models. They may even explain why the models utterly failed to foresee the cold that slumped south onto Europe recently. Just as it only takes a single pebble to start an avalanche, a single miscalculation can mess up a computer model.
Although the models did not see the cold coming, Joseph D’Aleo and Joe Bastardi on their blogs at the Weatherbell site did say we should be on guard for cold waves to hit Europe, as the autumnal patterns were similar to years in the past that saw cold waves hit Europe. They didn’t explain how it was going to happen in a step-by-step way, so I watched very carefully to see if I could see the steps as they occurred.
Back on December 12 we were seeing south winds bring warm air flooding north over Scandinavia, as the Atlantic storms veered north towards the Pole. A lot of Barents Sea was above freezing. Cold air was exiting the Arctic down the east coast of Greenland.
This pattern continued on December 14
And peaked around December 17
By December 19 the storms were no longer heading up to the Pole, but were moving east along the north coast of Russia. Barents Sea was cooling down, and to the east of the storm cold Siberian air was drawn up over the Arctic Sea and then dragged back west, and the milder Atlantic air lost its influence over the Pole.
By December 21 the new storm track had the east winds to its north starting to drag cold air back towards Scandinavia. The following Atlantic Gale didn’t bring such a flood of warmth north.
By December 24 the new storm track had penetrated weakly to the Pacific side of the Pole, and chilled Pacific air was being drawn over the Pole, but was too cold to warm the Pole much, and the cold air over the Pole was heading south to Scandinavia, and below freezing temperatures seeped down the coast of Norway.
By the 26th of December the cold was building over the Pole, and the strongest low pressure was east of Scandinavia, transporting Siberian air back west over its top towards a Barents Sea that was now far colder, especially to its north. The Pole was as cold as it ever gets, except on rare occasions, and the weight of that dense air was spreading out, including down towards Europe.
Today we see the following North Atlantic low is weak, without a surge of southerly winds, and the isobars hint of a discharge straight from the Pole to Scandinavia and areas further south.
This afternoon’s map shows the weak low bringing snow to Britain and the cold continuing to press south over Europe.
The computer models didn’t see this cold coming, even a few days ago, but now much of western Europe is below normal. As this cold continues to press south it is likely create elongated high pressure west to east. There may be a warm-up over Scandinavia as winds turn west to the north of the high pressure, but east winds to the south of the cold high pressure will bring very cold Siberian air further and further towards the Mediterranean, and a southern storm track will bring snows to Italy and perhaps even the north coast of Africa, before the cold is moderated.
However I have no business talking about Africa in a post about the Arctic, so I’ll just show the graph of temperatures north of 80 degrees latitude, which informs us the arctic is loaded with midwinter cold, and has plenty to spare.
Besides dumping cold down on Europe, some is being dumped south into Canada and the western USA. The thing to remember is that not only the Pole creates cold, but all areas of Tundra and Taiga generate cold as well, during these shortest of days. Better look for where you left your mittens.
(These maps are created by Dr. Ryan Maue at the Weatherbell site.)