Anchorage had another snowy winter. Is climate change to blame?
A blockbuster winter comes on the heels of other winters with heavy snow in Anchorage. Is this a trend, and is climate change to blame?
As of Jan. 29, Anchorage, Alaska, had seen more than 100 inches of snow this winter. That’s the earliest that amount of snow has ever accumulated since record-keeping began.
Anchorage, Alaska, has had a very snowy winter, following a blockbuster season last winter. Is climate change making Anchorage snowier?
Calling it a "pandemic of snow," The Associated Press reported earlier this winter that roofs in the city, located in the south-central part of the Frontier State, were collapsing under the weight of the unusually abundant snow.
Isil Mico takes a photo of her sister-in-law Oznur Mico in front of Snowzilla, a snowman measuring more than 20 feet tall, in Anchorage, Alaska on Jan. 10, 2024. (AP Photo/Mark Thiessen, File)
Snowzilla, a 20-foot-tall snowman that was built in front of a house in Anchorage in 2005, reappeared this season for the first time in 10 years, owing partially to the massive quantities of snow.
How snowy was this season in Anchorage?
Weather analysts use the meteorological winter period of December through February for official winter season records, which started in 1954. This puts the city in its fifth-snowiest winter at 78.6 inches.
Another measure, significant for off-season snowfalls that frequently happen in Alaska, is an expanded winter season that still overlaps years, measuring from July 1 to June 30.
By that measure, which includes major snowstorms that occurred last November, Anchorage has had its fourth-snowiest winter, with 123.4 inches so far, versus a historical average of 73.7 inches. The city crossed the 100-inch (8.3-foot) mark on Jan. 29, 2024, the earliest on record. The snow season of 2011-2012 holds the all-time record of 134.5 inches.
The top 10 snowiest seasons in Anchorage, Alaska 1954-2024.
And it hasn't been just Anchorage that has measured copious amounts of snow. Juneau, 580 miles southeast of Anchorage, also experienced an unusually snowy winter, but it is not one that would fall in its top 10 snowiest on record. Snowfall added up to 117.3 inches for the July-June period -- 34.2 inches above the historical average.
Snowfall departure for July 2023 to Feb 2024 in Alaska, expressed as a percentage of the 30-year 1991-2020 normal. The graph shows a slight increase in snowfall for the state since 1940. (Brian Brettschneider)
According to a map and graph climatologist Brian Brettschneider generated for AccuWeather, the snowfall departure from the historical average this season was positive for most of the state of Alaska this season, meaning more snow than average, although results were mixed. Overall, there has been a slight increase in the state's snowfall compared historical average when looking at the state average.
This is the fifth season since the turn of the century that falls into the top 10 snowiest seasons on record for Anchorage. However, Brettschneider points out, "Two of [Anchorage's] lowest snowfall winters, including our lowest [in 2015-2016], have also occurred in the last decade."
Plot of meteorological winter snowfall (Dec-Feb) for Anchorage Alaska. (National Weather Service)
Although weather records only go back to 1954 in the Anchorage area, a graph provided by the National Weather Service showed that seasonal Dec. to Feb. snowfall is slightly increasing over the long term. This is unusual, as two-thirds of continental U.S. weather stations see less snow than they did 50 years ago, according to Climate Central.
What's to blame for the recent snowy winters in Anchorage?
A warmer Gulf of Alaska is a huge factor.
"Sea surface temperatures over the Gulf of Alaska have warmed an average of 1-2 degrees Fahrenheit over the past 30 years," said AccuWeather Senior Meteorologist Brett Anderson, noting that El Niño added additionally to the warm ocean temperatures this winter.
"This warming trend in the waters of the far northern Pacific has added more fuel to storms approaching southern Alaska, leading to higher rates of precipitation and in this case, most of that was in the form of snow this past winter, as the air remained just cold enough in the Anchorage area," Anderson explained.
More specifically, Anderson said the jet stream this season contributed both to the additional moisture and kept the cold air in place in the southern part of the state.
Can we blame climate change for increasing snowfall in Anchorage?
According to another map Brettschneider provided, which comes from the ERA5 Reanalysis dataset, most of Alaska is getting more snow than 50 years ago, 18% more on average. This is not the case, however, for the continental United States, where the percentage is close to zero, with more stations losing snow than gaining, as Climate Central noted.
Snowfall trend for December to February in Alaska, expressed as a percentage of change from 1974-75 to 2023-24. (Brian Brettschneider)
Scientific American wrote in 2017 about a study that concluded that climate change has contributed to a 117% increase in snowfall in the state of Alaska since the mid-19th century. Reasons for the increase were the warmer waters and stronger storms in the Gulf of Alaska, as Anderson mentioned above.
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