Weather Outside Your Window: Record-shattering cold has gripped Alaska and refuses to let go

Sunday, December 5, 2021

Record-shattering cold has gripped Alaska and refuses to let go

Much of the U.S. has been experiencing a fall heat wave, but it’s an entirely different story in Alaska.

By Mark Puleo, AccuWeather staff writer

Published Dec. 3, 2021 6:05 PM EST | Updated Dec. 5, 2021 6:47 AM EST

As thermometers continue to display unusually high temperatures for the month of December across the contiguous United States, the states outside of the lower 48 are facing extreme weather situations of their own, from blizzard warnings in Hawaii this weekend to record-shattering low temperatures and blizzard warnings in Alaska.

Amid the West's wacky month of record-breaking warmth, record-breaking rain and record-breaking snowlessness, Alaska had its month for the history books, albeit in a very different chapter.

Bristol Bay Borough – which was the state's very first county back in 1962 – is home to Katmai National Park, serves as the easternmost arm of the Bering Sea and was also host to the coldest temperatures in the country last month, as the town of King Salmon endured their coldest November on record, averaging only 4 degrees F, while Cold Bay averaged 27.7 degrees.

According to the National Weather Service, the areas weren't alone, as multiple other locations throughout the state endured one of their five coldest Novembers in history.

According to AccuWeather Senior Meteorologist John Gresiak, the dome of high pressure that has built over the western U.S., which has influenced the record-breaking high temperatures, has shifted storm patterns to the north. That ripple effect has kept cold air trapped in the northwestern portion of North America.

"To the north of the series of atmospheric river storms that have hit parts of western Canada and the northwest U.S., a very cold and dry air mass has settled over Alaska for the past few weeks," Gresiak said. "Even southern coastal areas which are often moderate have been quite cold."

Along that southern coast of Alaska, some of the weather factors that help moderate those cold conditions have been nullified.

Alaska-based climatologist Brian Brettshneider told AccuWeather that a number of influences are responsible for keeping that cold air trapped in Alaska for the entire month of November.

While it's no shock for Alaskans to see temperatures drop during meteorological winter as the state sees decreasing sunlight, Brettshneider said the trapped mass of cold air has prevented warmer air from trickling into the state to moderate temperatures amid the loss of solar energy.

Temperatures in Alaska at 4:30 AM local time on Dec. 4, 2021.

"An upper-level trough of low pressure was established over the western part of the state and it really hasn’t budged much in weeks," he said. "So you keep losing more and more solar energy, radiate it out to space, and again the upper-level low has prevented any moderating air from coming back in, so it just gets colder and colder."

On top of that, he said the icepack in the Bering Sea has been more established this season than in years past, which has also limited any of the moderating influences that warmer ocean waters could have.

And while the remarkably low temperatures are certainly noteworthy, Brettshneider said it's been the persistence of the cold that's truly been unusual.

"These types of features tend to come and go during the cold season, but this is has been very persistent, it’s been like anchored in place for weeks and that’s really been perhaps the most unusual part of it," he said.

For now, the unusually cold temperatures seem to be here to stay.