Alaska Early December 2025 Extreme Weather
Wind and cold to start the month
A short post to document a couple of the high impact/notable weather events in and near Alaska the first half of December.
Matanuska Winds December 5-9, 2025
The lower Matansuka River valley (typically Chickaloon to the Palmer/Wasilla areas) occasionally experiences very strong northeast winds. The well known “Matanuska wind” is predominately a late autumn to early spring phenomena and is an example of a katabatic wind. These winds typically develop when there is high pressure and cold, dry air over the Copper River basin and low pressure over the northern Gulf of Alaska. The pressure difference drives the air from high toward lower pressure and is funneled through the narrow Matanuska valley (Fig. 1).
The event December 5 to 9 was notable for both the intensity of the wind and the duration and caused widespread, multifaceted damage. A state disaster declaration was signed by the governor on December 9th. In addition to direct wind damage, long lasting power outages combined with temperatures in the teens and 20s (F) resulted in widespread frozen water pipes. A useful impacts summary is here. A quick review of the state disaster declarations since the early 1980s suggests that this is only the second wind storm in the lower Matanuska valley that produced damage sufficient to warrant such a declaration (the other was the January 2022 wind storm).
Plots of sustained and wind gusts at Palmer and Wasilla airports, where, amazingly, the power stayed on through the storm, illustrate the duration of the strong winds (Fig. 2). At Palmer, the event lasted 78 hours, and most of the times winds were regularly gusting over 60 mph. A peak wind of 100 mph was reported from the Palmer airport on the morning of December 7th. Other reported peak winds included 81 mph at the Alaska Department of Transportation weather station on the Glenn Highway near the Palmer Hay Flats and 72 mph at Wasilla Airport.
The surface analysis from the NWS Weather Prediction Center for 9am December 7 illustrates the strong pressure difference between the Gulf of Alaska and the western Copper River basin (circled area in Fig. 3.). In fact, it was likely even stronger than analyzed, as the aviation weather observation from Gulkana Airport, a few miles north of Glennallen, has not been available for weeks, but from other observations we know it was clear, calm and temperatures near -20F/-30C.
Early December Cold Snap
Following a very mild November and start to December, the first significant cold snap of the 2025-26 winter settled in across eastern Interior Alaska and the Yukon Territory December 6-12 (Fig. 4). Temperatures in the -50s (F) are not that common in December anymore, but Chicken, Tok and Northway all had four days that cold. The lowest reported temperatures were -56°F (-48.9°C) at Alaska’s perennial cold spot Chicken and -58°F (-49.8°C) at Faro, YT. At the Whitehorse, YT airport, the temperature bottomed out at -42.1°C (-44°F), the first -40C/F temperature there since December 2022.
The deep cold was broken by a fast moving storm that moved from the Russian far northeast to near Wrangel Island before turning eastward and racing across the southern Beaufort Sea, bringing blizzard conditions to the North Slope and pushing clouds and some snow across the Interior Alaska and the Yukon Territory. However, the cold is settling back in and I’ll likely have more low temperatures to report about in the end-of-month summary.
Incredible documentation of these compounding extremes. The 78-hour Matanuska wind event with sustained 60+ mph gusts shows how katabatic flows can create infrastructure crises that go way beyond just wind damage when you factor in the power outages and frozen pipes in subfreezing temps. The juxtaposition with interior temps hitting -56F the same week really underscores how Alaska's experiencing both ends of extreme weather simultaneusly.
Thank you ✨️