A massive winter storm is forecasted to dump feet of snow in the coastal mountains of Alaska. While the deepest totals will be found in the high-elevation backcountry, Alyeska will still pick up significant accumulations, likely in the 30 to 40 inch range by the time the precipitation is mostly wrapped up on Thursday.
The first big push of snowfall begins on Tuesday evening, coming from the south. This storm will be pulling warm, wet air from the Pacific, so temperatures will increase dramatically as that airmass surges northward. The heaviest snowfall rates will be found at high elevations, where colder temperatures will keep the snow density low and squeeze out more inches of snow per inch of liquid precipitation.
Snowfall rates will increase throughout Tuesday and continue to ramp up during the day on Wednesday. At Alyeska, snowfall rates will peak on Wednesday afternoon, likely sometime between noon and 6pm local time. During this time, snowfall rates at Alyeska’s mid-mountain will likely exceed an inch an hour, at points even more if a particularly strong band passes overhead. The ECMWF (European) model is putting the jet stream in a perfect position to create these heavy bands that will allow the totals to stack up very quickly; the American and Canadian models are both keeping the jet too far to the west for optimal squall formation.
Snow levels will also peak on Wednesday and should be between 1,250 and 1,750 feet. A particularly strong band of snow can drag this snow level down, but Alyeska’s base should see mostly rain during this system.
Most of the snow will be done on Thursday morning but will linger into Friday afternoon.
In terms of totals, Alyeska is looking at between 20 and 40 inches with the most likely range being 30-40″. Keep in mind this is at mid-mountain; the base will see almost all rain and snowfall totals will vary dramatically depending on elevation.