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Shifting seasons

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Lars on a trail break/Craig Medred photo

November brought winter like weather to coastal Alaska at last, ending another October of the new-normal.

The National Weather Service in Anchorage reported up to four inches of snow turning in places to rain. It was the kind of storm the state’s largest city used to see a month earlier.

People can have a lovely debate about climate change in the 49th state, but there is no doubt Alaska has been warming for a long, long time.

In 1794 when the H.M.S Discovery under the command of Capt. George Vancouver probed the Alexander Archipelago, Vancouver found a wall of ice to the north of what he dubbed Icy Strait. One hundred and five years later,  John Muir arrived in the north to find the ice had retreated 48 miles to form Glacier Bay. 

Today the converging glaciers that once filled the mouth of the bay with ice have retreated into inlets to the north, east and west of the main bay, and you can sail up one of them – Tara Inlet – to within spitting distance of the Canadian border almost 70 miles from Icy Strait.

And while the ice has been retreating in Alaska, the state’s forest have been advancing steadily northward and upward. 

Some of this has to do with global warming in general, but much of it appears linked to the vagaries of the ocean off Alaska’s coast.

As The Alaska Climate Research Center notes, “since 1977 little additional warming has occurred in Alaska with the exception of Barrow and a few other locations. The stepwise shift appearing in the temperature data in 1976 corresponds to a phase shift of the Pacific Decadal Oscillation from a negative phase to a positive phase.”

Climate change or…?

The “positive phase”of what everyone calls the PDO results in a lot of warm water in the Gulf of Alaska and that warm water has a big influence on Alaska’s climate. The PDO was thought to operate on a 20- to 30-year cycle, but that hasn’t exactly been the case in recent decades.

With the exception of a few brief periods since ’76, the warm phase has been dominant, according the Joint Institute for the Study of the Atmosphere and Ocean at the University of Washington, which has been tracking North Pacific water temperatures since 1900.

The JISAO, like the Climate esearch Center, deals in long-term trends, and tries to avoid the temptations of the short-term. But for average humans the latter can be hard to ignore.

A couple of decades ago, there were some givens if you lived in Alaska’s largest city:

There would either be significant snow blanketing the landscape by Halloween, or the ground would be frozen hard as rock. That is no longer a given.

If you were a waterfowl hunter, snow in the glacier-dominated Twentymile, Portage and Placer rivers at the head of Turnagain Arm would invariably bring an end to the brief Alaska waterfowl season by Oct. 10 or 15. No more.

The climate records for Anchorage sort of say it all. October in Anchorage this year was 4.4 degrees above the “climate normal period” of 1981 to 2010; last year was 1.1 degrees above; 2015 was 5.7 degrees above; 2014 was strangely normal, and 2013?

A whopping 8.2 degrees above normal. 

If you’ve thought Octobers in Anchorage milder than they used to be, you’re right.

Coastal Alaska now has its own “Indian Summer,” as warm, sunny, extended autumns were often called in less politically correct times. Indian Summer is now suspect because the term originated in Colonial America as an euphemism for “false summer.”

It was apparently tied to the idea the late-arriving humans invading North American from Europe thought the early-arriving humans who invaded from Asia had tried to fool the former into thinking nice fall weather meant a gentle winter to come.

One has to wonder if the term still carries the same derogatory connotations, given that it is doubtful that most people know the term’s origins. But sometimes it’s hard to get beyond the past. 

No snow, so?

But whatever you want to call these Octobers of above normal temperatures, most Alaskans – the most diehard skiers being the exception – seem to enjoy them. And you have to go back some distance in time now to find Octobers oscillating around the established norm instead of floating above it.

What it means no one can say. Climate is full of short-term variability.

But the phenomenon of later falls has been noticed by more than those living in Alaska’s very America-like urban core. The change has been noted in the state’s still wild hinterlands as well.

Scientists looking down from space have noticed ice-over on lakes along the Arctic coast is now almost a week later than it was 60 years ago.

Barrow, the nation’s northernmost city, was 6.9 degrees above normal in October this year. To the south along the Bering Sea, Nome was 3 degrees warmer. It was a positively frigid October in Nome compared to last year, which was 9 degrees warmer than normal.

Two-thousand-sixteen was the warmest year in Alaska history, and from Nome north into the Arctic the warm temperatures were even warmer than the new normal. Barrow was a staggering 12.9 degrees above normal in October 2016.

It has generally been this way all along the coast from Nome south and then east past Kodiak and south toward the Panhandle for several years, though Kodiak is indicating there might be a shift this year.

It was only 2.8 degrees above normal in October. If it’s a harbinger of a shift in the PDO, there is always the possibility the old Alaska could return even in these times of global warming.

“The period 1949 to 1975 was substantially colder than the period from 1977 to 2014,” because of a shift in the PDO, the Climate Research Center notes. It was during that period that the state’s record cold temperature was established.

The thermometer hit 80 degrees below zero at Prospect Creek north of Fairbanks on Jan. 23, 1971. The only word for minus-80 is brutal.

There are definitely worse things than global warming.

 

 

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1 reply »

  1. It wasn’t exactly balmy in Fairbanks at the Iditarod ReStart last March. I went to see the Ice sculptures and found -34 pretty brutal.

    Like

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