The only other winter with such a low snow depth in January was 2012-2013; that winter saw an even more extreme snow drought in the early going, but the snow depth then reached 5" on January 12 and 9" on January 15. So this winter now has the distinction of the lowest peak snow depth through this date. In a couple of days we'll also break the record for latest date to first reach 6" snow depth (January 14, 2013); the median date is November 17.
Here's a chart of the season-to-date snowfall and peak snow depth since 1949. (I'm not sure how the snow depth exceeded the snow total in 1994-95 and 1999-2000, but that's what the data say.) It's interesting to note the high volatility in snow totals in recent decades and especially in the last 5 years or so.
Why the lack of snow? The answer is that a blocking ridge over the Arctic Ocean north of Alaska has prevented cyclonic storm systems from reaching Kotzebue. The six maps below show the sea-level pressure anomaly (left column) and 500 mb height anomaly (right column) in October, November, and December of 2014; notice the general lack of low pressure in the north.
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The recent flow pattern can be contrasted with the situation in a very snowy month: below are the maps for the snowiest early winter month in Kotzebue's history, November 2003 (46 inches):
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Interestingly, all of the North Slope stations are above normal for their snowfall totals. This is probably due to the sea ice returning much later and a far longer period of time with sub-freezing air, not too cold, and lots of Arctic Ocean moisture. Their above-normal snow is probably not correlated with synoptic patterns.
ReplyDeletePerhaps even more impressive is the fact that Dutch Harbor has had 0.0" of snow so far. They should have had over 30" by now! The previous record latest first snow was December 8th.
Of all 1st order stations in the U.S. that should have received at least 20" by now, Kodiak is in last place with only 1.8" so far. Low snow all around. :(
Thanks for the additional details, Brian. Before I knew better, I would have said that unusual warmth is generally quite reliably connected with above-normal precipitation in winter in Alaska. Not so.
DeleteNo snow, or no precipitation?
ReplyDeleteGary
Good distinction, Gary. In Kotzebue and Dutch Harbor it's definitely both; Kotz is at 0.69" liquid equivalent since November 1, compared to normal of 1.25". Dutch Harbor is at 8.50" compared to normal of about 16".
DeleteHowever, Bethel is at 3.62" precip compared to 2.20" normal. And Kodiak has received over 34" of precipitation since November 1, the greatest on record for this period. So these have just been too warm for much snow.
"Mostly cloudy" is the mantra for Fairbanks NWS' forecasts. Not much precipitation has fallen here.
DeleteHave the stations with low snow or precipitation so far this winter been cloudy or clear? I'm just trying to gain an appreciation for this winter's conditions.
Gary
I don't have recent sky condition data conveniently at hand, so not sure. Reanalysis humidity at 700 mb shows generally clear in the northern half of the state since Nov 1, cloudy in the south (compared to normal).
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