The 2024 water year saw lower than normal precipitation across Arizona, and the hottest summer on record here. Those facts are perhaps not surprising. But, what might be a bit unexpected is that drought conditions in Arizona were a little better at the beginning of this October than at the same time last year.
Mike Crimmins, an extension specialist and climatologist with the University of Arizona Cooperative Extension, contributed to the Water Year Report from the National Integrated Drought Information System and joined The Show to talk about what it says and some of his key takeaways.
Full conversation
MARK BRODIE: The 2024 water year saw lower than normal precipitation across Arizona and the hottest summer on record here. Those facts are perhaps not surprising, but what might be a little unexpected is that drought conditions in Arizona were a little better at the beginning of this October than at the same time last year.
Mike Crimmins is an extension specialist and climatologist with the University of Arizona Cooperative Extension.
He contributed to the water year report from the National Integrated Drought Information System and joins me to talk about what it says and Mike, what to you are some of the key takeaways here?
MIKE CRIMMINS: The interesting thing is that we're, this report came out right in the middle of the just string of record heat at the end of a early retreating monsoon. So we were baking with these record temperatures hadn't rained much, especially in Phoenix over the course of the monsoon season and that kind of retreated early.
But the whole this report was detailing the water year. And so the water year is actually this period of time from October of the previous year through September 30th.
And so that water year, which is really tuned up to try to catch the winter as a whole in the middle was actually quite interesting for the southwest and I think we forgot that it was actually quite wet and cool last winter and into last spring. And so if you put all that together in a water year report, you get this interesting mix of cool and wet conditions followed by a somewhat miserable summer at the tail end of the water year.
BRODIE: Well, yeah, I mean, sort of to that point, you mentioned the report mentions that Arizona experienced its hottest summer on record which spans about 130 years. But then when you look at the actual map with the, you know, the increasingly, you know, dark shades of red indicating drought. The map from October 1st of this year looked a lot less dark red than the map from October 3rd of last year.
CRIMMINS: I know we've been kind of hitting the guard rails over the last couple of years and we can even go back to the really miserable summer of 2020 when we broke all the records as far as no monsoon precipitation across much of the state. And then since then, we've been kind of cycling between, we had two La Nina winters. La Nina winters typically give us drier than average conditions in the southwest.
One of those did the second, winter of La Nina actually gave us wet conditions and then we ended up having a quite dry monsoon last year of 2023. It was actually below average. Much of the state broke a bunch of temperature records at that point.
And then we actually had an El Nino event which typically gives us above average precipitation for the southwest come online last fall and it actually delivered, we, we ended up having a pretty good, winter, cool temperatures down a bit and brought us some decent precipitation.
And then of course, we can't, you know, have a, you can't enjoy that for too long. We went into this monsoon season and then pretty mediocre precipitation. Some parts of the state did, ok, came in an average, some real small areas had above average precipitation.
But I think as you know, in Phoenix, was not so great and so kind of the middle part of the state up into the eastern part of the state, parts of the southeast part of the state just really fell behind and then the heat, just set in and just would, it's still kind of holding on to us right now.
BRODIE: Right. Well, and as far as water goes, the report notes that Lakes Mead and Powell are still pretty far below where they ought to be.
CRIMMINS: Yeah, I mean, and those, the reservoirs operate on much, much longer time scales, you know, so we're hitting the guard rails from season to season and the decline in the big reservoirs. And that's really what they're designed to do is to kind of absorb all of these kind of shocks to the system at the shorter time scales. They've been trending down for many, many years.
And so we had a couple of good winters and that's the way that we would actually try to reverse that trend up with, with the rivers, but it's just not been enough.
And, you know, we're fighting against climate change as well where climate change, these warming temperatures just make the runoff efficiency, the ability of that snow to turn into stream flow gets into those reservoirs. We just lose that efficiency over time.
BRODIE: So I'm curious what you make of. So, you know, all of this, as we've been discussing sort of dichotomous data coming, obviously, you know, there's some logistical reasons for it and some sort of timing reasons for it.
But if you just read the report, it seems like there's quite a bit of juxtaposition of really good news and like not great news, all sort of rolled into one along with, as you referenced some surprises thrown in there about what, you know, what we got relative to what we expected. So I'm curious what you make of all that.
CRIMMINS: Yeah, that's pretty normal for the Arizona climate is, is all of these juxtapositions all the time. And, and it's the interesting thing about even studying drought here down in Arizona is that drought really is, there's no one definition for it. And so we have to think about it in terms of time scale.
So if you're worried about the reservoirs and you're thinking about stream flow in the Colorado River, it's big long time scales. If you're worried about fire, if you're worried about grazing, you're gonna be thinking about much, much shorter timescales on seasons.
So it's, it's not uncommon for us to end up having a good season or maybe two seasons of precipitation. And things actually really turn around and look quite good on the landscape. Maybe fire risk goes down.
We end up having forage for livestock, but at the same time, we can still end up having that drought signal in the reservoirs. So you can end up having a conversation about drought and it can be a good conversation and a bad conversation at the same time depending on what you're focusing on.
BRODIE: So, is any of this in any way predictive of what we can expect going into the fall and winter and spring of 2025?
CRIMMINS: Yeah. So one of the things that we rely on here in the southwest is we pay real close attention to the seasonal outlooks issued by the climate prediction center, which are really finely tuned to the El Nino southern oscillation. And so right now, we're looking at La Nina forming, this one's been really quite interesting. It's been very fickle, quite slow to form.
The models aren't super sure how strong it's gonna peak at, but there's still a decent chance we'll have a weak La Nina event that will come online kind of midwinter. And typically, what that does, for us is it, it moves the jet stream pattern, to the north.
And so that will take some of those storms out of play that we would really rely on to give us an above average or average winter and probably lean us into the below average precipitation category for, for winter precipitation. So right now again, this is imperfect science from the forecasting perspective. Right now, we're leaning towards a below average precipitation forecast for the upcoming winter and probably above average temperatures because when it's dry here, it's typically warm.
BRODIE: Right. Well, so then does that make, assuming that comes to pass, would that make the monsoon season next summer more important in terms of trying to sort of keep pace with getting some amount of precipitation?
CRIMMINS: Yeah, that's exactly right. We really, and that's, I think really interesting feature about Arizona that I think we live, we live down here and we, we know this, but I don't think we appreciate the fact that we have two wet seasons.
We have the winter, which is very unique. You know, it's upper elevation snowfall. It's typically these long duration, low intensity precipitation gives us soil moisture that leads into the spring time. And then the monsoon is the other season that we were really rely on this precipitation is that it's really hard for us to string together two average seasons, let alone three.
And so, yeah, we ended up having not a great monsoon, I think, by all accounts, if this winter is dry, we're really gonna start sliding back into those short term drought conditions. You're gonna start seeing the US drought monitor, which we're already seeing start to fill back in across Arizona. And then we will really look to the monsoon season to hopefully start on time.
And so, yeah, we're already thinking, you know, eight months out what next monsoon might look like.
BRODIE: All right, that is Mike Crimmins, a climatologist with the University of Arizona Cooperative Extension, also an extension specialist there, Mike, thank you very much. I really appreciate it.
CRIMMINS: Thanks, Mark, good talking with you.
