Alaska wildfire researchers grapple with changing climate’s effects on predictability

The Kwethluk Fire on April 22, 2022 when it was estimated to be 9,693 acres. (Alaska Division of Forestry photo)

It may seem strange to talk about wildfires in December. But it’s worth noting that all the snow falling on Alaska now doesn’t mean much for next summer’s fire season.

Take last spring. In Southwest Alaska, one winter’s snow melted prematurely, sparking fires earlier than usual in a part of the state that isn’t as fire-prone anyway.

So what happens to fires next summer?

That’s the work of Uma Bhatt, professor of atmospheric science at the Geophysical Institute at the University of Alaska Fairbanks. In March, Bhatt and her team will try to predict how bad the coming fire season will be.

But right now, Bhatt says, they’re trying to understand why they were so surprised by the early start last season.


The following transcript has been edited slightly for clarity.

Uma Bhatt: Things have changed in Southwest Alaska. As the season progressed and we gathered information from different people, it makes a little more sense as to what happened. But I remember being shocked in April when the Kwethluk fire broke out and we were sitting in all that snow in Interior Alaska. And that created a lot of smoke and disrupted a lot in this part of the state that’s not really used to fire. And the other interesting feature of this fire season was that in interior Alaska it started very abruptly and ended very abruptly. So we look at the temperatures in May, June, July and the precipitation in May, June, July. And then we look at the start of the long rains. It usually rains at the end of July. And this year they came in with a vengeance and ended the fire season pretty quick, pretty quick. But that doesn’t always happen. Delaying those rains could change the fire season.

Casey Grove: It’s almost like we were unlucky with all that rain, it could have been a lot worse, right? Is this one of the takeaways?

Uma Bhatt: Absolutely. Yes. And so in our forecast analysis we’re trying to figure out the predictability in what I call the long rains, the rains that start in late July. Can we predict them on a seasonal level? Are there some clues in the climate system that we can look at, say in May or June, and say, “Okay, we think the rainy season is going to be on time.” And that’s also a really important question to ask answer to get a handle on what kind of fire season we’re going to have.

Casey Grove: Yes. Just going back to how unusual it was that the snow had melted earlier in this part of the state. I mean, the fact that there was a lot of snow in many parts of Alaska is a little misleading to think, “Oh, there’s a lot of snow or there’s been a lot of precipitation, and that’s going to affect our fire season.”

Uma Bhatt: Yes. And one story I tell is that May 2004 was one of the wettest Mays ever. And I remember thinking to myself, ‘Oh great, we’re not going to have a bad fire season.’ And that, if you remember, was our record year. And speaking to fire analysts, it was probably that May rain that caused a lot of vegetation to grow. So it actually increased the amount of fuels. And I think another thing I’ve learned over the years, we can have big fire seasons, but they can come in many different ways. And I think this year was another type of fire season that burned over a million acres in southwest Alaska and broke all records for that part of the state.

Casey Grove: Well, I’m guessing there’s something like, whatever, 500-, 600- how many hundred-pound gorillas in the corner of the room that we haven’t mentioned yet, which is probably because the Climate change plays a big part in that too, right?

Uma Bhatt: I think climate change makes it harder to predict things. And if we look at our records, it looks like the flash is increasing. We are not 100% sure as lightning sensors have changed over time. But I think we’re getting more and more confident that it looks like the number of flashes is increasing. So this is related to climate change and the warming of our atmosphere. The other thing that seems to be happening is that we’re getting more convective precipitation and less widespread precipitation. That’s how extensive our long rains in July are. But the convective precipitation is those cumulus clouds that we get in the summer. And these are typically associated with lightning, and they seem to be increasing across the state. And they’ve been increasing, especially in southwest Alaska. And just based on the acres burned above our record over the past 20 years, we’ve had most of our extreme years during that time. So yes, in addition to all the different processes, these processes, you know, are being optimized by what the climate is doing at scale under climate change.

Casey Grove: This also includes the type of fuel. Did you mention that you spoke to local people there who spoke more about what grows on the tundra?

Uma Bhatt: Yes, my tundra specialists have documented an increase in vegetation. But I also meet with elders in Southwest Alaska. And I’ve been doing that for about 10, 10, 11 years now. And usually we just present different climate analyzes and people talk about what they see on the ground. And that was a very common observation in southwest Alaska that everyone said, “I used to be able to see very far from my house, and now there’s so much undergrowth.” And again, I think these southwest Alaskan fires are now in the Are able to burn in the tundra simply because there is a lot more shrub biomass. Fuels are changing, the climate is changing, the weather is changing. That’s probably why we got these very early season fires.

Casey Grove: I understand that it can be a messy process and that it can be difficult at this point. But, Uma, I have to ask, you know, summer of 2023, Alaskan wildfire season, it’s December right now, what’s your forecast?

Uma Bhatt: So we will give you this prediction in March. I don’t have the data yet. We need to better understand where the predictability lies in the observations. You know, we have some information, and I think El Niño status is an important predictor. So that didn’t quite work out this year because it was a La Niña in March. And typically, La Niñas don’t result in a major fire season. And that’s exactly what didn’t happen. So yeah, I’m not comfortable making that prediction just yet.

Casey Grove: That kind of reminded me of that famous quote, I think it’s Donald Rumsfeld, you know, “There are known knowns and known unknowns,” and it’s like, you kind of have to identify those things by the way it sounds.

Uma Bhatt: Yes. And that’s what we do with our group. And then we can use that information to improve the capabilities of these dynamic weather models. So that’s the strategy we’re working on.

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