Alaska, one of America’s fastest-warming states, is locked in another long and alarming stretch of unusually high temperatures.
Parts of the state are on pace to finish March more than 20 degrees above average, which is an extreme deviation from the norm in U.S. weather records.
In recent days, the warmth has reached a pinnacle.
Temperatures in interior parts of Alaska stayed above freezing for multiple nights in a row for the first time so early in the year on record. Readings this weekend are projected to end up 30 degrees to even 50 degrees above normal across northern parts of the state.
This is just the latest round in a longer-term episode of acute and persistent warmth across the state and the Arctic region.
Yet this round is unusual and historic, the likes of which has never observed over such a long stretch at this time of year.
“Deadhorse, AK, is set to finish March about 23 [degrees] above normal for the month,” Brian Brettschneider, an Alaska-based climatologist, tweeted Wednesday.
The location on Alaska’s North Slope is vying for the most extreme monthly temperature anomaly ever recorded in the United States during March. “The most above normal March was Circle Hot Springs, AK, in March 1965,” where it was 20.9 degrees above normal, Brettschneider wrote.
In landlocked Fairbanks, the temperature did not fall below 34 degrees either Tuesday or Wednesday. This was the first time during the month of March there have been consecutive above-freezing lows in Fairbanks. Before this stretch, the earliest instance of back-to-back above-freezing lows in Fairbanks happened more than two weeks later, April 15-16, 1978.
This warmth is right on the heels of a heat wave that set a number of all-time March warmth records in the region just over a week ago.
During that spell, “Klawock, Alaska topped out at 70 degrees Fahrenheit. That marks the earliest 70-degree Fahrenheit day ever recorded in Alaska,” wrote Earther’s Brian Kahn.
February was also unusually toasty in the Last Frontier, ranking among the top 10 warmest. The past 12 months rank as the third warmest on record for the state. For the past four- and five-year periods, nothing rivals the warmth of the present.
Alaska has seen significant late-winter warming over the past 50 years, and February’s warmth fit right into that pattern. But the extreme warmth observed so far this month is more of an anomaly.
“Over the past 40 years there is not much of trend in March temperatures,” wrote Rick Thoman, a climatologist based in Alaska. While northern Alaska has exhibited substantial warming in the month, much of the rest of the state is mixed.
Nevertheless this March is behaving like so many other recent months in the 49th state. Since January 2013, it will become the 29th month to rank in the top 10 percent of warmest months since 1925.
And the warm pattern is set to continue.
This weekend, high pressure is scheduled to strengthen its grip on Alaska, so an additional string of records seems likely to fall in the days ahead. Weather models have the most significant warmth again focused on northern Alaska, where readings are projected to range from 30 degrees to 50 degrees above normal.
The cause for the current warmth is a stagnant and strong zone of high pressure at high altitudes that has been centered over northwestern Canada and into Alaska. At the same time, persistent low pressure over parts of the Bering Sea has helped draw warmer air in from the south.
By mid- to late next week, there are some signs this high pressure will begin to weaken and shift.
Given the persistence of weather patterns in the region, which is something that appears to be a symptom of climate change, we may have to believe any change in regime when we see it.
All this warm weather, in addition to a stormy pattern over the Bering Sea, has resulted in multiple episodes of open water over areas that very rarely see it in winter. The lack of sea ice, which reflects sunlight, amplifies warming over the region.
Sea ice along the Alaska coast and the Arctic more broadly remains way below normal. The February values in the Bering Sea were the second-lowest on record, behind 2018. Both were huge departures from prior record lows.
These signals are all consistent with expectations in a warming world. If anything, the northern reaches of Alaska and the Arctic more broadly have warmed even faster than anticipated.