Heavy Snow in Copper River Basin, Alaska

DOT reported up to 7 inches of snow on the Richardson Hwy between mileposts 42 and 82 at 0845 January 28th. Additionally, travel was severely hampered for the duration of the snow event as areas along the Richardson Hwy, including Thompson Pass, were closed due to heavy snow. Additionally, a Borough Official reported a storm total snow amount of 16 inches at 0800 January 29th in McCarthy, a town affected by the road closures.

Between January 28th and January 29th, a strong low pressure system organized over the Gulf of Alaska, then moved north towards the Prince William Sound. This low was able to interact favorably with an extremely cold air mass entrenched over the southern Mainland, producing very high snow to liquid water ratios for the duration of the snowfall event across much of Southcentral.

The deep layer of cold air was able to stay mostly in place across the Mat-Su Valleys and Cook Inlet region as moderate to heavy snow moved in near the approaching low. This lead to the extremely unusual combination of surface temperatures between 0 and 5F and heavy snow that lasted for many hours between 1/28 and 1/29. This storm had widespread impacts to travel due to the prolonged nature of moderate to heavy snowfall rates for numerous locations.