The beginning of the end of the year 2019 – the warmest in Alaska history – drew to an end in the state’s largest city in the style of the new-normal weather to which many in state’s urban core have grown accustomed.
From the top of the Hotel Captain Cook, the view of rain splattering down on snow-free, 45-degree downtown streets looked more like what one would expect to see in a Seattle suburb than Alaska on New Year’s Eve.
Within hours, however, that was history, and the old normal was on its way back. The temperature by midnight had dropped to 25 degrees and snow was falling heavily. By noon on New Year’s day, the National Weather Service reported snow depths of 7 inches to almost 22 inches spread across the Municipality of Anchorage.
And Old Man Winter was only warming up (or should that be cooling down?). When the snow ended, the 25-degree temperature of early New Year’s day just kept going down, down, down.
A low of 3 degrees on Jan. 2; minus-3 degrees on the third, the first time Anchorage had gone below zero in several years; minus-9 on fourth; minus-10 on the fifth; and minus-11 on the 6th. A similar low was forecast for today at the city’s official weather station with temperatures in city neighborhoods closer to the Chugach Mountains than Cook Inlet expected to drop below minus-20.
Good-bye Seattle; hello International Falls, Minn., the self-proclaimed “Icebox of the Nation.”
As the ice flows grew in Inlet waters largely ice-free only a week earlier, some recent Anchorage arrivals unfamiliar with weather like this were forced to ponder “where went that global warming thing?”
Though warm winters in Alaska’s largest city might have started to look like the new normal, that sort of thinking ignores the reality of weather, which yo-yos year to year, and climate which is defined on the basis of 20-year or longer trends. The Weather Service at this time uses the average of 30 years to define its climate “normals.”
A lot of variation can hide within a 30-year average.
Alaska annual temperatures – like those across the rest of the northern hemisphere above 60 degrees latitude – have crept upward since 1900. But the shift has been anything but a steady increase.
Down, down, down
Statewide, Alaska was generally in a cooling phase from 1950 until about 1975, and then everything changed.
The climate shifted warm in 1976, according to the Alaska Climate Research Center, and for 24 of the next 36 years annual state temperatures were above normal. They looked to be cooling near the end of the 2000s.
And then they skyrocketed.
As the Weather Service notes, the five warmest years on record in Anchorage have come in the last six years. The cold winter in that six-year span was 2017, which still ranked 22nd in a local climate record dating back to 1917.
There is no reason to believe the latest cold snap is the beginning of the end of this years-long warming trend, but there is also no reason it couldn’t be. Though atmospheric levels of carbon dioxide – the main gas insulating a sun-warmed planet to keep it from turning into just another frozen rock hurtling through space – appear to have been steadily climbing since around the start of the Industrial Revolution, the linkage between the gas and global warming is not so clear.
European scientists who earlier this year reconstructed the global climate of the Last Interglacial (LIG) period 120,000 to 129,000 years ago noted that the Earth was at that time warmer than it is today even though the “greenhouse gas concentration was comparable to the preindustrial period, with carbon dioxide around 275 parts per million (ppm) and methane around 700 parts per billion.”
Atmospheric carbon dioxide is now at an unprecedented 407.4 ppm.
Why we are all aren’t cooking, or drowning is unclear. The study by Paolo Scussolini from the Institute for Environmental Studies at Vrije University Amsterdam along with colleagues from Norway, Germany, Sweden, France, China, the United Kingdom and the U.S. also concluded sea levels during the LIG were nine to 10 feet higher than at this time.
Baffling even experts
Weather is already known to be hard to predict, and as data continues to collect over the decades to come, it is possible the same will prove true of climate.
Judah Cohen, an expert on the polar vortex, was Monday admitting the latest shift in the swirl around the North Pole that brought cold to Alaska caught him by surprise. An MIT researcher, Cohen writes a highly informative blog for Atmospheric and Environmental Research, a company that provides weather risk assessments for businesses and the government.
“I certainly entered this winter confident that the stratospheric polar vortex (PV) would be perturbed and have been surprised so far this winter by the resiliency of the PV to disruption…,” he wrote. “I also expected that low Arctic sea ice and a relatively warm Arctic would favor high latitude blocking/high pressure.”
That hasn’t happened as the northern hemisphere moves into what is officially winter. As a result Alaska is now starting a winter looking more like the old normal than the new normal.
“….Since late December,” Cohen observed, “the strong PV has coupled to the surface contributing to expansive low pressure in the Arctic and relatively cold temperatures in contrast to my own expectations. And typically, when the Arctic is cold the mid-latitudes are mild.”
All of Alaska falls under this Arctic influence and thus the well-known coupling between Anchorage the American Heartland. When it’s warm here, it’s cold there and vice versa. While Anchorage residents shivered in the subzero cold on Tuesday, the high hit 40 degrees in Chicago.
What all of this means, Judah was hard-pressed to say.
“Though I see little support for a significant disruption of the PV in the near future, with the possible exception of possible Scandinavian blocking the latter half of January, if the PV stays strong right through the end of winter that would be highly unusual in itself, especially in the era of accelerated Arctic warming,” he wrote.
Sea surface temperatures off the Alaska coast remain unusually warm, but still Cohen wasn’t offering much hope at this point for those wishing for another unusually mild winter in the Anchorage metro area where most Alaskans live.
From now through the month, he wrote, the patterns “favor normal to below normal temperatures across Alaska, much of Canada and the US along the Canadian border,” but there could be some more snow. There is always that hope for skiers and other winter sports enthusiasts.
And for those who worry about Arctic sea ice, there is good news. It has been growing rapidly given the cold.
“At the close of December, sea ice growth had gained enough ground for daily extent to rank only seventh lowest, the highest at this time since 2014,” the National Snow & Ice Data Center reported today.
‘December 2019 sea ice grew by an average 31,700 square miles per day. This is faster than the 1981 to 2010 average gain of 24,700 square miles per day) and is the third fastest December ice growth rate in the satellite record, behind 2006 and 2016.”
Ice coverage in the Bering Sea remains below normal, but the latest satellite imagery showed the ice extent south of the Seward Peninsula and closing in on Saint Lawrence Island.
Inland in the nation’s coldest, darkest state, temperatures along the Yukon River were in the range of 40 degrees below zero to 50 degrees below zero which made Anchorage seem almost balmy.