Last week I alluded to the linkage between the Pacific Decadal Oscillation and seasonal snowfall in Anchorage, with a negative PDO phase often producing increased snow relative to normal. Of course the PDO also influences seasonal temperature variations - a negative PDO typically brings colder conditions to Alaska, especially in the south.
These twin correlations imply that seasonal mean temperature and snowfall are also correlated to each other in Anchorage: increased snowfall tends to accompany cold. Here's a chart illustrating this relationship in the last half-century.
I thought it would be interesting to look at the snow/temperature relationship elsewhere around the state. I started by examining ERA5 reanalysis data, but it's not particularly helpful: it actually suggests a positive correlation in the Anchorage area, presumably because the model's resolution is inadequate (i.e. the results reflect the influence of conditions at higher elevation).
However, one region where the model likely gives a good picture of the low-elevation snow/temperature relationship is in Arctic Alaska. In the far north, warmer conditions are favorable for increased winter snow, simply because of increased availability of moisture. This is supported by data from Utqiaġvik up until measurements ceased in 2019: warmer winters tend to be more snowy.
However, historical data from Kotzebue and Nome do not have a positive correlation, despite what the model says.
How about the interior? The relationships are weak, with little correlation, although there's a suggestion that the warmest winters tend not to be very snowy in McGrath and Fairbanks (especially the latter). Particularly for Fairbanks, this presumably reflects the drier weather that occurs when the pattern favors warm downsloping/chinook winds from the south and southeast.
Data from Bethel suggests a hint of a negative correlation like Anchorage: more often than not, colder-than-average winters are also snowy.
These charts probably give a good sense of how seasonal snowfall is likely to trend over time if Alaska's climate continues to warm in future decades. Broadly speaking, we would expect winter snow accumulation to diminish in the low-elevation south and to increase in the Arctic, while the interior may remain relatively unchanged. But of course large annual and decadal variability will continue, and there may be long-term circulation changes (e.g. related to the PDO) that have significant impacts on long-term trends.
I'll be happy to add charts for other locations upon request (if the data is adequate).
