Despite a relatively snowy winter, it’s been pretty dry across Alaska this spring and early summer.
It’s been so dry, in fact, that the U.S. Drought Monitor is set to declare drought conditions for a huge part of Southcentral Alaska.
That breaking climatological news comes to us from National Weather Service climatologist Brian Brettschneider, back for another Ask a Climatologist segment.
Brettschneider says, as a whole, the month of May was dry but mostly average in terms of temperatures. But for Southcentral, he says the second half of May was the second warmest on record.
The following transcript has been lightly edited for clarity.
Brian Brettschneider: With earlier snow-off in the spring, the sun really starts warming the ground a little a week or so earlier than it used to. And so we see springs are warmer and particularly fall we see as notably warmer. But there’s a strong long-term trend toward warmer springs, really throughout the entire state.
Casey Grove: And that’s, even if we have a good snow year, that’s related to the snow melting off sooner?
BB: Correct. Snow on the ground acts kind of like a mirror for solar energy. It just hits it, reflects it back off into space, it’s like it never happened. And when you don’t have the snow, then the ground becomes like a sponge, just absorbing all that solar energy. And so that snow-off date is really important. It’s something we track closely. And that has been trending earlier and earlier.
CG: So speaking of precipitation, so far this spring, what have we seen?
BB: Yeah, really, in most the state, we’ve seen very little precipitation since the last part of April. And there’s a couple of paradoxes. So here in Anchorage, we’ve seen almost no precipitation for the last five or six weeks. And pretty uniformly, no matter who you ask, they say, “Yeah, it’s really dry out.” This is the fifth wettest year to date, you know, through the end of May for Anchorage. And so it really kind of begs the question, “Well, does that precipitation in January and February — that was snow — does that really even matter now?” And what we’re finding is, really, it doesn’t. And to that effect, it’s been so dry that the U.S. Drought Monitor, which is a little bit of breaking news, it’s going to come out tomorrow, and it’s going to show areas from about Talkeetna through Anchorage, down to the western Kenai Peninsula classified as in drought. And that’ll be about, you know, 60 or so percent of the state’s population. So we have a newish term for that, that we call “flash drought,” and that is kind of a rapid onset drought. So a lot of your standard drought metrics which, as an aside, don’t work especially well in Alaska. They would say, “Oh, well, look, the last six months were one of our wettest years on record. So there’s no way there can be a drought.” And we kind of say, “Well, what happens kind of before the snow melts off, you know, for grasses and forest, doesn’t really matter. It’s what happens after the snow is gone that matters.”
CG: So a lot of the conversations I’ve had with people about the weather lately have gone something like this. “Man, it’s been really nice. But I kind of worry about this.” And they’re talking about the fire danger, of course. And as somebody that is very in tune with what those actual numbers are — are you personally worried about that?
BB: Yeah, so fire, of course, is a big concern. Whenever it’s dry, you need a couple of things for fire early in the season. Before the convection starts, you know, fires are basically human started. You really need kind of a a convergence of atmospheric conditions as well. So you need warmth. And you need, usually, breeze. And you also need low relative humidity. An interesting aspect to our warm spell that we’ve had the last 10 days or so has been extreme low humidity. And that has really, you know, turned up the dial on on the fire danger.
CG: So maybe we’ll cross our fingers and knock on some wood. But what are we looking at here going forward? And is there a chance that any, you know, significant records could be broken here in the near future?
BB: Well, there’s a number of ways we can look at it. So far for this early in the season, we’re in Anchorage, we’re expected to be 70-plus for the first five or six days, approximately, of the month. So once we end the first week of June, well, we’ll pretty easily have our most 70-degree days on record for this early in the season. I think we’ll probably tie it Wednesday. And then we’ll just keep adding to it the next few days.
The first draft of the summer outlook appears to be tilting warmer than normal, and there’s not much of a signal for wet vs. dry. And, of course, our wet season in most of the state — or at least the mainland part of the state, generally, the second half of July into August — is when it really starts to rain a lot. And that’s what happened in 2019 in Southcentral. Everyone remembers that it was a bad drought. It was so dry. Well, if you look at the year as a whole, it’s actually kind of unremarkable. But what was remarkable is it basically didn’t rain the entire summer, and especially in August, when it supposed to rain a lot, it didn’t rain. So it’s really the timing of the precipitation that can also be a big contributor to drought conditions or, later in the season, fire conditions.