The extent of Arctic Ocean sea ice may be lower than average for the middle of a northern winter. But don’t try telling that to coastal Alaskans.
Bering Sea ice grew to the second highest extent on record during January — covering about 217,000 square miles of ocean and complicating an extraordinary ice-breaker-assisted delivery of fuel to Nome. That ice cover was about 23 percent above the average observed by satellites during the past 34 Januarys and was only about 26,000 square miles less than the all-time record set in 2000.
“Overall, Arctic sea ice extent remained lower than average in January,” reports the National Snow and Ice Data Center (NSIDC) in its newest monthly analysis. “However, in the Bering Sea, ice extent was much greater than normal. The heavy ice cover caused problems for fishermen and made for an arduous late-season resupply mission to Nome, Alaska.”
Another wrinkle: “The Arctic Oscillation, which had been in its positive phase most of the winter, switched to a negative mode, bringing cold weather to Europe and changing the direction of sea ice movement.”
What explains the Bering deep freeze? The same overall weather pattern that walloped Interior Alaska with 50-below-zero temperatures and buried Alaska’s coastal communities in snow.
The satellite jockeys at the snow-and-ice center point to a complex configuration of lows and highs that brought extra cold air down from the polar regions, driving the ice farther south than normal and, in the process, delivered Alaska one of the coldest Januarys on record.
“The weather pattern, which has persisted since November, features unusually low surface pressure south and east of the Alaskan coast, which leads to winds from the north or northeast that blow into the Bering Sea region,” the snow-and-ice center explained here. “This weather pattern also brought moist air from the Pacific Ocean to the southern Alaska coast, helping to explain record snowfalls in Alaska towns such as Cordova, which received more than 15 feet of snow between early November and mid-January.
“The extensive sea ice impeded winter fishing in the Bering Sea and slowed an important fuel resupply mission to Nome, on the west coast of Alaska. More information on sea ice conditions off southwestern Alaska, and a full-resolution version of the image at left, is available on the NASA Earth Observatory Web site.”
Still, it hasn’t exactly been a return to ice-age bliss for the polar pack. January ice extent averaged about 5.3 million square miles — the fourth lowest ever observed during the 1979-2012 age of satellites and about 425,000 square miles below average for this time of year.
To put the first month of 2012 into perspective, an ice-covered habitat almost as large as California and Texas combined was missing from the January Arctic.
“As in December, ice extent was lower than normal on the Atlantic side of the Arctic, especially in the Barents and Kara Seas,” the NSIDC explained. “The greater-than-normal ice extent in the Bering Sea partly compensated for low ice extent on the Atlantic side of the Arctic Ocean, but ice extent as a whole remained far below average.”
A different measure also suggested that an especially frigid Bering Sea hasn’t changed the ice-loss game. The total volume of ice — the surface footprint combined with the ice unseen below the surface — remained below average for January, according to the latest chart posted by the Polar Science Center at the University of Washington.
“Ice volume for January 2012 was (3,887 cubic miles), slightly larger than last year (3,791 cubic miles) but 41 percent lower than the maximum in 1979 (and) 28 percent below the mean,” the analysis said here.
These latest developments come after a particularly debilitating September, when sea ice shrank to one of the smallest summer extents of the past 30 years. The existence of an ice cap helps stabilize the world’s climate. its loss speeds up climate warming because darker open water absorbs more solar energy than reflective white floes. The loss of summer sea ice means destruction of habitat for healthy populations of polar bears, walruses and seals.
Contact Doug O'Harra at doug(at)alaskadispatch.com