Alaska’s North Slope sees record-breaking heat, among state’s other climate oddities

Alaska’s North Slope has seen all-time record temperatures this week, with Deadhorse hitting 89 degrees on Tuesday.

National Weather Service climate researcher Brian Brettschneider — back for our Ask a Climatologist segment — says that was due to the combination of a Chinook wind and a higher background temperature in the age of climate change.

That’s also as Alaska as a whole saw its wettest July on record and different regions of the state are experiencing other major impacts from climate warming, including the glacial outburst flooding in Juneau.

But Brettschneider says, among all the exceptional effects of climate change, that heat on the North Slope takes the cake.

Listen:

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This interview has been lightly edited for length and clarity.

Brian Brettschneider: So it reached up to 89 degrees in Deadhorse. Another station just south of Deadhorse was 88, I believe. Nuiqsut was 88. Utqiagvik set a record. Barter Island, Kaktovik had an August record. So (it was) really just widespread, unusual and historic warmth for probably the eastern two0-thirds of the North Slope.

Casey Grove: Pushing 90 degrees.

BB: Right, so if you look at Alaska, the warmest temperature any official station has observed all year is 91, and there’s two stations that have done that, one near Fairbanks and one over by Eagle. So to have basically the third-warmest temperature, you know, in the entire state this year, or the fourth warmest, be up on the North Slope, is really quite remarkable.

CG: Yeah. Well, that leads me to several questions, like, what? Why? How? How could this happen?

BB: It is important to first address the climate change component of it. So the whole North Slope is warmer than it used to be. So to have extreme temperatures is now easier if you have a an unusual weather pattern, like we did. So in the case of the record warmth, you know, you had this confluence of events. You had this deep southerly flow, a Chinook flow, south of the Alaska Range, and then another Chinook kind of north of the Alaska Range. Very dry air, very warm at the mid levels of the atmosphere. Everything came together to maximize the warmth potential up there. But again, we’re now starting at a higher baseline, so it’s easier to set those all-time records.

CG: And for folks that don’t know or don’t remember, what is a Chinook? And are we talking about a double Chinook? Is that what you’re saying?

BB: Well I wouldn’t call it double Chinook, but a Chinook is where you have winds coming down the the slopes of a mountain. They heat up adiabatically, compressional heating, and so just the fact that that air is forced downward in elevation causes it to dry out and warm up.

CG: And I mean, maybe people are still looking at this as we speak, but what sort of impacts would you see on the North Slope from 88-, 89-degree temperatures?

BB: Well you can think about it in a couple of ways. One, you can think about it in terms of, what are the ecological impacts? And then what are the human impacts? And so certainly, ecologically, having those kind of temperatures is not compatible with permafrost, even if they’re only fleeting for a few days at a time. Going around the world, you don’t see permafrost exist concurrently with places that can get that warm. So, that’s kind of a bad sign in and of itself.

You know, as far as the impact on people, of course, we have thousands of people that are working up there and living up there, more so working in Deadhorse, but living in other places. And I imagine it was quite the experience, you know, with all the mosquitos and and other considerations for living up there, it’s probably not like living in the big city where you can just throw on a pair of shorts and flip-flops and maybe enjoy it for a day or two. It’s probably quite uncomfortable, if I had to guess.

CG: Yeah, no doubt. I feel like we’re going to go all over the state today, because there’s interesting weather and climatological things happening all over the place. But the state as a whole also had a very wet July, right?

BB: Yeah, so if you look at, you know, if you average all the corners of the state, it looks like we just beat out, I believe, 1959 for having the wettest July on record, statewide. And some stations had their single wettest, particularly along the west coast, and then down to Juneau, the single wettest. And many other places had like a top five wettest. But usually, because Alaska is so large, if there’s one part of the state that’s really wet, maybe other parts are pretty dry. But that really wasn’t the case this time. It was dry, like around Kodiak, but most of the rest of the state was significantly wetter than normal in July, and that is reflected in this this July record.

CG: I wanted to ask you about the glacial outburst flooding in Juneau, which seems, you know, as bad as last year but not maybe with as much damage. Or, I think we’re still maybe figuring that out. But, you know, one thing a friend of mine from Juneau expressed to me was that this glacial outburst flooding is going to be this bad, you know, every year.

BB: Well the glacial outburst flood, you know, certainly has a strong and maybe a complete climate change component to it. I mean, it’s the result of excessive meltwater filling this kind of side basin, the Suicide Basin, up so much that it eventually has to force its way out from underneath. And this is going to happen for the next few decades, until the Mendenhall Glacier finally retreats behind the the outlet for the Suicide Basin.

So last year, the river got up to 15 feet, and this year it got up to 16 feet. And, you know, there is a max amount of water that can be held in the basin. So I think part of the height that the river can reach is how fast that water can be evacuated. And it certainly happened this year, and it probably didn’t help that the day that it was released, the water was released, was a record high temperature in Juneau, so that probably contributed extra meltwater to the system that might not have been there if it had released a few days earlier. So yeah, this is something that’s going to be happening every year, and I can’t predict the severity every year, but certainly two years in a row of record severity might be an indication that that the system is finding its its equilibrium position.