Ask a Climatologist: A look back at Alaska’s second La Niña winter in a row

Spring has sprung in many parts of Alaska, while winter is merely hanging on in others.

Back for our Ask a Climatologist segment, National Weather Service climatologist Brian Brettschneider is holding on to wintry thoughts, as we’re now able to look back and analyze the winter that was.

And Brettschneider says there are several takeaways from this slightly colder and snowier second La Niña winter in a row.

Listen:

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The following transcript has been lightly edited for clarity.

Brian Brettschneider: (A prediction of a) La Niña gives us, in most cases, a pretty good idea that we’re going to be cooler than normal. In much of the state, it actually ended up working out. North of the Alaska Range, and then in Southeast Alaska, it was a little bit below normal, you know, one to three degrees below normal. Here in Southcentral, it was actually kind of above normal. It was one to even, say, four degrees warmer than normal. So about three-quarters of the state was below normal a little bit, with the biggest departure up around Kotzebue, and for about a quarter or maybe even a little less it was warmer than normal, with the warm bullseye pretty much right over Anchorage.

Casey Grove: My experience here in Anchorage, is that spring has sprung. Is that accurate?

BB: I think that’s fair to say. You know, it’s now late April. It’s unlikely we’re gonna get any more measurable snow. I mean, from this point on in the season, if you add up all the winters, there’s been barely 12 inches of snow after this date. Now, April 25, 2008 in Anchorage had almost two feet of snow. So it can happen. But it’s not going to happen this year.

CG: I remember that. I was a delivery driver at the time, so that was quite significant for me.

BB: Yeah, but even the next day, the roads were basically bare pavement, even though there was snow piled up everywhere. Just with the high sun angle, the way it is now, it goes pretty quickly.

CG: So we’re talking about snow statewide. How did we shape up with snowfall for the winter?

BB: This was a pretty big snowfall winter for most of the state, maybe except for the Southwest to lower Yukon, lower Kuskokwim Delta. But most of the state had a really big snow year. You know, Fairbanks and Anchorage got about 90 inches. Juneau over 100 inches. All of those are significantly above normal. If you look at the the SNOTEL stations, the snow courses that the USDA does, they’re above normal almost everywhere. And so you have to go probably north of the Brooks Range to find any sizable area that had below normal snowfall in the winter. But statewide, it was it was a big snow year.

CG: I know we’ve talked about this a little bit in the past, but is there a climatological explanation for that, that there would be, you know, more precipitation in general, maybe in a warming climate?

BB: Well, it’s a complicated question. In general, yes, we expect more precipitation to fall in a warming climate. Now, as far as snowfall, as you warm up the air, say from 20 degrees to 25 degrees, it can hold more moisture. So we would expect more snow, all other things being equal. What we’ve really seen is kind of the snow season starting later and being kind of squeezed into the middle. But in that middle, we’ve been still getting our typical or even, in some cases, more than typical amount of snow. But that can only last for so long. As you keep warming things up, you’re just going to change more of that snow into rain. And that’s just an inevitability of thermodynamics.

CG: So what are the implications of a good snow depth and having had a fair amount of snow in terms of wildfires and things like that? I mean, kind of looking forward, do we see mostly benefits from that in the spring and summer?

BB: Most of the state, this is the driest time of the year. And so if you lose your snowpack early, like they did in Southwest Alaska, and it warms up and it’s windy and things can dry out, then, you know, stuff can catch on fire, like we see about a 10,000-acre fire out there burning right now. So that’s always the early season concern. Now, people often try to extend that and say, “Well, okay, a big snow winter, that’s going to be good for the fire season overall.” And what you find is there’s literally no correlation. You could have the biggest snow winter on record, and it makes almost no difference of how much fire acreage you’re going to get burned in the middle of summer.

CG: It seems like it’s probably too early to say much about river breakup, and my understanding is that can be kind of on a case-by-case basis. Is there anything that we can say, knowing what we know now, about what we might expect from river breakup, even if it’s just in general terms?

BB: So the Alaska Pacific River Forecast Center, they issue breakup outlooks, breakup forecasts, and they have input from people in different communities, webcam observations, pilot reports, and they actually do their own River Watch flights, where they observe conditions themselves. And the initial forecast is for, in most areas, for breakup to be a couple of days late. And like you said, it varies from river to River, the conditions, how the ice formed, how much snow is in the the upper part of those basins that might run off and move ice around. So a lot of individual variability, but they’re generally looking at about two to five days later in most places.