Anchorage is locked in a cold snap after last week’s warmer, icy weather — but that doesn’t mean fresh snow is coming anytime soon.
As part of our Ask a Climatologist segment, National Weather Service climate researcher Brian Brettschneider says despite the current chill, this November ran warmer than normal — and that broader warming trend is likely to continue.
This interview has been lightly edited for length and clarity.
Brian Brettschneider: October normally gets about five inches of snow, at least here in Anchorage. And this year we didn't really have any. I think we may have had 1/10 of an inch. Now historically, October snow is what I call “novelty snow.” You know, it falls, but it doesn't usually stick around. We usually have a warm spell. And historically, for Anchorage, the onset date for our continuous winter snow pack, where it doesn't go away, is Nov. 8. And this year, it started on Nov. 7. So we were right in line with when we should get our winter snow pack.
Wesley Early: What's the longer term outlook for this winter? Does it look like we're heading into a repeat of last year, where it was warmer than normal, with very little snow during sort of the heart of winter?
BB: Yeah, last winter was really, really unusual, at least here in Anchorage. We went November, December, January and February with almost no snow. Four months, really the heart of the winter, with no snow. But we had a lot of snow in October, and we had a lot of snow in March and even April. And so the totality of the winter was we were a little bit below normal, but nothing remarkable. But the snow that did fall was in the part of the season where it melts pretty quick. So it wasn't here for the dark, cold season. As far as this winter, we're in a La Niña winter for the second year in a row. That does tip the scale toward a little bit colder and a little bit snowier for Southcentral, so that's kind of our best guess. But there's other indications in the climate system that would tend to push us away from being cold and snowy. So it's really a lot of uncertainty. The safe bet is it's probably going to be at or warmer-than-normal and near-normal precipitation.
WE: So this month started off with icy conditions in Southcentral leading to road accidents and school closures. There was even a Mat-Su bus that overturned while they were taking kids to school. As Alaska continues to warm because of climate change, do you see these types of icy conditions to be more common?
BB: Well, I think there's two ways to think about it. One is the overall warming temperatures. And so you know what used to be a 31-degree storm now might be a 33- or 34-degree storm, and that's going to, in many cases, transition that snow over to rain. The other ingredient in that is our Chinook events. And so a lot of times, our icy conditions… in fact most of the time, our icy conditions are results of a Chinook bringing in warm air and kind of melting the snow and then it refreezing. And historically, that's probably when, at least my recollection is, ASD cancels school more times than not, is for those Chinook melting events, not freezing rain events like we've had here during the last week. So we should expect more of the freezing rain events. We should probably expect a similar number of Chinook events moving forward.
WE: And a big question every year for many people in the area, when does it look like there's going to be a lot of snow in the near future?
BB: Over the next two weeks or so, it's actually looking quite dry, and the reason for that is we are expecting kind of an extended cold snap. And there's always a chance that there could be a little storm system that slips in during the cold snap. But for the most part, when we do have those long, extended cold snaps, they're pretty dry, and so I shouldn't get people's hopes up that we might have a lot of snow coming here in the next two weeks.
WE: What's causing this cold snap, and how long do you think it's going to stick around?
BB: Much of the month of November, we've had kind of high pressure sitting over the state, and that made the state pretty warm. But that high pressure is going to redevelop more toward the Bering Sea and the eastern part of Siberia, and the flow around that will bring in air from the north, and that allows what we call an Arctic trough to drop in from the north. And that's a very cold air mass and a very cold flow, and it's coming from seas that are frozen over, and there's just not much moisture in it. And so the combination of those two, the northerly flow and the fact that it's coming over basically an area with a lid on it, where no moisture can get in, is going to bring A, cold and B, drier conditions. And that should probably last for a while. You know, in the winter, when we get these, it's not uncommon for them to last several weeks in a row. Right now, it's hard to predict things more than about two weeks, but all the guidance says we should be pretty chilly below normal for the next several weeks in a row.
