Is more wild weather on the way for the western U.S.?

It was a remarkable winter in the western United States with phenomenal snow and heavy rain. Now that things have quieted down, UCLA climate scientist Daniel Swain joins the meteorologists to discuss what's next.
What will happen as all the snow melts? What will this year's wildfire season be like? Will the atmospheric rivers return next winter? It's a deep dive into all things weather and climate across the West on this week's episode.
About the Across the Sky podcast
The weekly weather podcast is hosted on a rotation by the Lee Weather team:
Matt Holiner of Lee Enterprises' Midwest group in Chicago, Kirsten Lang of the Tulsa World in Oklahoma, Joe Martucci of the Press of Atlantic City, N.J., and Sean Sublette of the Richmond Times-Dispatch in Virginia.
Episode transcript
Note: The following transcript was created by Adobe Premiere and may contain misspellings and other inaccuracies as it was generated automatically:
Hello, once again, everybody. I'm meteorologist Sean Sublette and welcome to Across the Sky, our National Lee Enterprises weather podcast. Lee Enterprises has print and digital news operations in 77 locations across the country, including in my home base in Richmond, Virginia. I'm joined by my meteorologist colleagues from across the sky, Matt Holiner in Chicago and Joe Martucci at the New Jersey Shore.
My colleague Kirsten Lang is taking some well-deserved time off in Tulsa for a couple of weeks. And guys, we've got Daniel West on the podcast today. A lot of people know him as Weather West. Why are you shaking your head at me? Daniel Swain. Okay. Daniel Swain. Daniel Swain. He's Weather West. Yes. You all knew where I was going with you?
Of course. Of course. Without a doubt. Without an end. And he's great. I mean, I've done some work with him when I was with the Climate Central. He's just got a wonderful, wonderful grip on what the weather and the climate are in the western part of the country. And it's really, really nice. Yeah, well, you know, Shawn, it's a good follow up from last week's episode where we talked with Donnie down at the Placer County Department of Public Works about all the snow that they plowed.
So we have the boots on the ground with your last episode with Donnie. This time we're taking it from the academic perspective and the forecasting and a look back perspective with Daniel Swain. So it's a good one two punch as we really exit out of the cool season, and then we promise we'll talk about warmer and more summery things as we go forward over the next couple of.
Yeah, this is a real interesting conversation with Daniel because he's just, you know, really focused in on the West. And I think oftentimes, you know, as meteorologists in the central and Eastern part of the country, because it seems like a lot of the time there's not much going on in the West, so it doesn't get discussed much. But, boy, this winter was truly the exception.
There was lots of talk on the National level about what's going on out west. And, you know, it kind of like shifted a tinge. It's like, wait a minute, I thought the you know, nothing happened in the West. It's just constant, never ending drought. And wildfires. Well, this is this year was the proof that you can't forget about what's going on our way because it's not going to be drought all the time.
It's not going to just be wildfires all the time. They're still going to get big rains. They're still going to get big snows and look at the impacts that it cause. And of course, Daniel is tuned in with the West all the time and is aware that it's not this drought going on out there. So he was the perfect person to bring on and really dive into.
This is a fascinating discussion. Yeah, it really was. We're glad to have him. So let's cue it all up and get our discussion started with Daniel Swain there at UCLA. And our guest this week is Daniel Swain, climate scientist at the Institute of Environment and Sustainability at UCLA and author of the popular Weather West blog and YouTube Channel.
He has been featured on numerous digital and legacy broadcast outlets talking about weather and climate in the Western U.S. And we are absolutely delighted to have Daniel on the podcast. It has been so busy, I know for you, Daniel. Thank you so much for joining us on the Across the Sky podcast. Thanks again for having me. Glad to be here.
I do want to talk about some of the big picture items down the road, but first, let's talk about immediacy. These next, let's say 1 to 3 weeks there in California, of course, with the phenomenal amount of snow. Everybody kind of gets that. But now it's starting to melt and we've got kind of a hot spell actually developing.
So what does this kind of portend or kind of lay the groundwork with regarding flooding there in California in the coming, let's say, one, two or three weeks? Well, I think you've nailed most of the key points there. But it's I think it's worth digging into a couple of them because, you know, California, just to review, you had an exceptionally wet winter in the central part of the state, which includes the southern half of the Sierra Nevada mountain range and really phenomenal amount of snow accumulated tens of feet at the higher elevations in these places.
And so currently the water stored in that snowpack in the southern Sierra is on the order of 2 to 3 times the average amounts, a 2 to 300% of average, which in some places in the far southern Sierra is the largest amount ever observed at this point in the season. So there is a huge amount of water up there, the vast majority of which is still yet to melt.
And all of that melt is eventually going to end up in rivers and streams that drain, mainly down the western slopes of the mountain range into California's Central Valley and the San Joaquin Valley and Tulare Lake Basins in particular. So all of that water that's up there in the mountains right now, a snowpack is eventually going to make its way to lower elevation areas and probably given this heat wave that's going to ramp up later this week.
So a lot of that's going to melt sooner rather than later. Can I get you to talk a little bit about to Larry Lake? I've just become aware of this over the last three or four weeks. I did not know that there was an actual lake there decades and decades ago, but there has been a change. So what is that all about there and about what part of California is that?
Yeah. To every lake is or was I guess was and perhaps will be a maybe is the best way of putting it given what's going on right now the largest freshwater lake west of the Mississippi. This is quite a substantial body of water in the southern San Joaquin Valley of California. It was indeed a century or so ago drained mainly, so it could be used for agricultural purposes.
But but also a number of people now live within this historic lake bed, which is sort of maintaining itself in most years from becoming a lake again by having lots of levees and dikes and conduits, artificial interventions to keep the water away, essentially. And in recent years, recent drought years, you know, flood risk has been far afield. People haven't really been thinking about it.
But now that we've got got a very wet winter in this part of the state, now that we have this enormous snowpack upstream, a lot of that water is accumulating in this basin and there is no outlet to the ocean and to very lake based and of the flooding gets very severe and it spills over the top of the basin into the San Joaquin River.
The water that flows into Tillery Lake Basin, it it stays there, it accumulates. And so all of that we're hearing about all this flooding, that water isn't going to by itself just gradually drain out to the ocean. That water is just going to sit there and continue to get deeper as more and more water flows in. You know, so one challenge in addition to all the water that's flowing in from snowmelt and rain this past winter, is that the ground itself has subsided, literally sunk in the Tillery Lake Basin in recent years due to groundwater pumping during severe drought.
So we're actually seeing probably flooding that will be deeper and more prolonged here in this wet spell because of the drought conditions that just ended and the human response to that drought being to pump all this water out of the aquifers, the ground has sunk in some places by ten or more feet. So this is not a barely measurable thing.
This is you know, I'm I'm six foot four and the ground has sunk by, you know, considerably more than my height in recent years. That's going to affect the flooding in ways that are, I think, hard to predict from the outset. Yeah. Before I turn this over to Joe, I know you want to go next, but can you give us a little more idea of how big this lake is?
I'd say compared to someplace like the Great Salt Lake. Is it about that size? Half of that larger just for some kind of frame of reference? Well, I don't have the numbers off the top of my head, but, you know, it's it's the challenge is it's, you know, this especially this type of lake doesn't have a fixed size.
During the great flood of 1862, for example, much of the Central Valley all the way from the southern San Joaquin up to the northern Sacramento, I mean, that's 250, 300 mile stretch that was contiguous, inundated. It actually become one giant freshwater lake, almost 300 miles long, encompassing areas that are now home to millions of people and most of California's agriculture industry.
So, you know, if you measured it, then it would have been, you know, a truly enormous body of water. If you measured it last year, there's zero. It didn't exist. So it's you know, we often think about about bodies of water as these dynamic fix things. And that's that's almost never the case. But it's especially wasn't true even in its natural state for 244 to Larry Lake this was something that waxed and waned greatly from year to year before human intervention.
It has done so less since we drained it. But in the big years it's going to come back. And this year, you know, to very Lake is making a big time reappearance. Hey, Daniel, it's Joe here. I want to take a step back and get into your initial interest in weather here and maybe extreme weather. I know you went to, I believe, UC Davis for your bachelors and then got a Ph.D. from Stanford.
What drove you to be interested in whether there are any getting into the subset of the field that you're in now? Well, I was always a bit of a weather geek, maybe more than a bit of a weather geek, too, if I'm being totally honest. So actually my initial my undergraduate degree is in atmospheric science. So I actually specifically wanted to to pursue, you know, being a degree program that would give you the credentials to become an, you know, an operational meteorologist day to day weather forecasting.
And so I do have that degree. But then at some point in this process, I realized, you know, I'm still really interested in weather, but the big societal and scientific problems that are really interesting these days really seem to be sort about this weather climate nexus. So, you know, I'm really fascinated by the day to day variations in weather.
I enjoy cloud watching and watching storms and things like that. But also, you know, and that's where the societal impacts come from, right? Like climate change is affecting all of us. It's affecting ecosystems everywhere. But exactly how is it doing? So usually it's doing so by changing the envelope of extreme weather events, you know, shifting the range of what's possible or what's likely from what it used to be.
And so it turns out that this is kind of a niche that's underdeveloped or is certainly have been for for decades, where weather scientists, meteorologists and climate scientists were kind of siloed from each other. They're kind of viewed as different disciplines. But it's always struck me as a little bit odd because it's the same atmosphere and it's the same physics and chemistry.
There's this different time scales. And so, yes, you often use different assumptions, but I think that that separation has perhaps been too strict and too rigid. So I live a little dangerously and I mixed my my weather and my climate. They are different things, of course, But you know, what is climate? But the the you know, weather in aggregate, that's something I often like to say, because it's not just the average of weather, but it's also the extremes of weather.
It's it's the swings in whether it's the variability, too. So for me, that's sort of that that weather climate nexus is what really I think fascinates me. And now that I'm you know, I'm a climate scientist who has a background in meteorology and really thinks about climate change from a weather weather up perspective, if you will. Hey Daniel, it's Matt.
And going off of that, I kind of want to take a step back and look at the bigger picture because there's been a lot of buzz lately, of course, about all of these atmospheric river events and the improvement in the drought situation, even the removal of drought, particularly in California. But when you look at the big picture, I think what's getting lost a little bit is people think that the West is now completely drought free and that's definitely not the case.
In fact, in some parts of the West, there's still some extreme drought, not in California anymore, but other parts of the West. And so what can you say about, you know, the longer term trend? Yes, we had this really wet winter and there was improvement in drought across the West, but is this going to continue? Are we going to go back to drought?
What can you say about the general western U.S. in general and the outlook for drought? There is an important point because this has been, of course, a good water year in California and actually across much of the lower Colorado basin, which is the area in crisis because of the very low levels of flow on the Colorado River and all the big dams you hear about Lake Powell, Lake Mead, and sort of the the growing crisis there with water scarcity.
This, of course, helps in the short term in these places where, you know, there's been a good snowpack in the lower Colorado basin, there'll be better inflows into these reservoirs this spring and summer than there have been in recent years, that's for sure. But it certainly, as you say, it doesn't solve the long term problem because this really took decades on the Colorado Basin to develop.
So one good year certainly doesn't erase decades of accumulated water scarcity. And in California, I think the situation is a bit different because a lot of California gets its water for more local watersheds. So the northern two thirds of the state sees water mainly for the form of local reservoirs and then also snowmelt from the Sierra Nevada. And here, you know, the drought, I think it's fair to say, has broken.
But there's this broader question of what drought means in a warming climate, I think, which is really actually quite an active topic of research and conversation, because it's not entirely obvious. And a lot of what's happened in the West isn't so much because of lack of rain or precipitation, but it's more just that temperatures have been so much warmer in recent decades than they were in the 20th century that the evaporative demand, literally the thirsty ness of the atmosphere, its propensity to act as a giant sponge and extract water out of the landscape as it increased.
This is known as the increasing vapor pressure deficit in technical terms. And what it does is it just extracts more and more water out of the landscape more quickly. And unless you're seeing more precipitation than you used to on average, which were not, then there's going to be an accumulated deficit over time. So it's not just a question of the low precipitation years, but it's also a question of the high evaporative demand years, which increasingly have been almost every year, both the wet precipitation years and the dry precipitation years.
So what does it mean in a warming climate to have individual episodic wet periods? Do they completely counterbalance the accumulated, increased atmospheric sponginess, if you will, all the rest of the time? The math really doesn't pencil out because you'd need to get a lot of extra precipitation for that to be true. And we're not seeing a lot of extra precipitation now in California in particular.
And that is probably true to somewhat lesser extent in most of the West. We don't just expect to see drying in the future. In fact, in California, the hydro climate signature of climate change really appears to be increased variability. We call it increased precipitation or hydro climate whiplash because of how it kind of feels like to just wildly swing from dry to wet and back and forth.
And this again comes from that that sort of that that basic thermodynamics of the atmosphere, that increased atmospheric sponginess, as I mentioned, goes both ways. It both increases the atmosphere's ability to extract water out of the landscape. Think of a you know, a larger and larger dry sponge soaking more and more water up off your counter and you still a glass of water or something.
But on the other hand, that progressively larger sponge, once you've soaked up that water, you can wring out more water too, in the form of more intense precipitation. So in California, the signature really seems to be more of both, more of the very dry conditions on the one hand and more of the very wet conditions on the other.
And I think this is largely going to be true across much of the southwest. So in the long run, of course, if you only take the average, that might pencil out to be similar. But in practical terms, does it actually feel similar? No, not not at all. This is a radically different regime, You know, with with you know, either you're very wet or you're very dry increasingly, but you're really rarely in the middle.
And I think we've seen that a lot this decade where parts of California in particular have seen both record dry conditions and record wet conditions, in some cases more than once in the past decade, where we've broken the century long precipitation records and then also broken a century long non precipitation or dryness records in the same decade in the same place.
I want to that point about getting so much precipitation at once. There's also been a lot of discussion about about groundwater, especially in California and in the Central Valley in particular since so much of the wintertime. Vegetables certainly are grown there. When we have a situation like we had this past winter, How much does that help with with groundwater?
I mean, obviously we're still we're still very dry in the longer term. But would you say that this also helps the groundwater situation or at least buys us a little time? Well, this is a pretty complicated question, and I'm neither a geologist nor a hydrologist, but the situation is complicated, mainly because it's not just a question of pouring a bunch of water on the ground and hoping and it soaks in.
Unfortunately, we've done long term damage to the aquifers themselves by so much pumping and fracturing. I was talking about subsidence earlier, literally the ground sinking. The reason why it's sinking is all of that or space where the the essentially the air bubbles, not only bubbles but the spaces in between soil particles and in between rocks has become compressed over time.
And so that compression you've lost the the the the space where the water would have gone aquifers generally, you know, some folks think of them as these huge open caverns where water sits. That's really not what they are. They're they're actually it's just the accumulated effect and that effect of huge amounts of small air pockets that can fill up with water if the soil gets saturated, if you compress those air pockets enough, they don't magically reappear when you dump water on top of the ground.
Now, the water just kind of likes to sit there on the top of the ground and cause flooding and then runoff into rivers and into the ocean eventually, rather than soaking in nicely. So unfortunately, there's some long term damage we've done. Geography is in some places it makes it harder for them to recharge when we do get wet.
Years like this. And the other reality is that in general, even in a you know, even in an ideal, an undisturbed water system, there are only some places where aquifer recharge happens at a good pace. There are some places where naturally the soil is just too full of clay a rock. To really allow rapid recharge, you need to have you need to have, you know, water sitting there for years, not just for one season.
And so for these reasons, I think that the groundwater problem is not remotely going to be solved by even one, maybe not, probably not even by two consecutive very wet winters. It certainly helps, but it mainly helps because what it means is that there's less desire to pump water out of the ground. So it helps mainly in an indirect way because it means that there are fewer straws sucking that water out of the aquifer because there's water available elsewhere.
There is some recharge going on. There is movement to actively facilitate that recharge as a groundwater management and flood control strategy in California, which I'm optimistic about moving forward. But it's tricky because just because there's a lot of water doesn't magically mean that you've recharge aquifers and you know, this is going to be an ongoing problem, unfortunately. So.
So know that that part of the long term scarcity problem is definitely not solved by one really good year like this one. And it also underscores the need for a cross-disciplinary work between the geologists, the hydrology artists and meteorologists and climate scientists. We're going to take a little bit of a break, then we'll come right back with Daniel Swain and talk about El Nino, talk about some atmospheric rivers.
When we come back on the Across the Sky podcast. And we're back with Daniel Swain. Weather West on the Across the Sky podcast talking about the very wild winter and the repercussions for that in the western United States. So, Daniel, we've just come off the third consecutive LA Nina, which oftentimes means that it's drier than average and all signs are are pointing toward going into an El Nino, into this late this summer, into perhaps this coming winter, which oftentimes means wetter than average, not always, but oftentimes.
How do you kind of reconcile those things? I mean, we know that it's not 1 to 1, but but how do you kind of reconcile those things to do the public? Yeah, this is become actually a really major and consequential weather and climate science communication challenge in California because the it's probably helpful to think a little bit to review the history actually of El Nino in California in pop culture first, because really the first El Nino event of prominent public dialog was back in the early eighties and this was the 1982 83 event, which was a very exceptionally wet year in California.
There was a lot of flooding and there were a lot of problems. And, you know, folks in the media really linked that event to the very wet conditions that occurred at that point. And with good scientific reason. The scientists agreed. Then there was another big El Nino event in 97, 98 of similar magnitude, which was again a very wet winter in California with lots of flood related impacts.
And so that really reinforced this public idea that major El Nino events were were wet years in California. Then in 2015, 2016, there was another strong El Nino event and everyone got excited about how it was going to break the drought. And then it didn't. It was not an exceptionally wet winter in California, did not experience, you know, significant drought relief as a result that year.
Now, you know, we're heading into another year where indeed, as you say, it does look quite likely, I would say probably 80 or 90% chance at this point that an El Nino of some magnitude will emerge later this year. But interestingly, the public dialog is now centered, including in the local media, around how El Nino is so uncertain that it doesn't matter.
And I think we've swung too far back in that direction. It is absolutely true that El Nino is not everything, and there are other influences that in some areas can completely override its influence and produce an opposite outcome even. But on the other hand, there are a lot of pretty basic physical science reasons why especially strong El Ninos in particular, really should and do influence the hydro climate of the American Southwest pretty profoundly and know, as you say, it's not a perfect relationship.
But I think the challenge is a lot of folks go and try and do a literal linear correlation between the the El Nino surface ocean and surface temperatures anomalies and average annual precipitation. And of course, that signal is pretty weak in a lot of places. But if you focus only on the strong events and you focus specifically on El Nino, which is a bit asymmetric from its counterpart, La Nina, we'll talk about that a bit in a minute.
But there still is a pretty strong signal. So, yes, if El Nino is strong, despite the failure in 1516, I would still put my money on a wider than average winter, perhaps a greatly wetter than average winter, especially in central and southern California and in some parts of the lower Colorado basin. So there's usually a dividing line in El Nino and La Nina years separating the Pacific Northwest from the rest of the West.
And usually it's the opposite sign. So when the Pacific Northwest is dry, the rest of the West is often wet and vice versa. And usually in El Nino, the wet conditions occur in California and the Southwest and in the Pacific Northwest is dry and long on any of the opposite is true. We're lining as wet in the Pacific Northwest and dry in the in the Pacific southwest.
Of course, that's subject to some some variability. But but, you know, I think that that's a pattern that in the long run still holds true for reasons that physically make sense. But let's back up for a moment and think, okay, so what what is El Nino and La Nina? What is this in the first place? Well, technically, it doesn't directly have anything to do with the western United States.
It's a tropical ocean temperature oscillation that is strongly coupled with the tropical atmosphere. So El Nino simply means that that ocean surface temperatures in the eastern part of the tropical Pacific Ocean have been warmer than average for a sufficiently long period and long. Nunez and which means that ocean surface temperatures in the eastern tropical Pacific have been cooler than average for a sufficiently long period.
So there need not necessarily be any specific conditions in California or the American West for an El Nino or a La Nina to occur. And it's worth noting that even in 2015, 2016, where the rains did not come in great volume to California, the prediction for a strong El Nino event was correct. The strong El Nino event occurred in the tropical Pacific Ocean.
It just didn't produce the results that some folks had anticipated. And, you know, there's been lots of research on why that is is probably been in the weeds for this conversation. But I think in the long run, I would still put my money on a particularly for a strong El Nino event. And it looks like there's a decent chance that's where we're headed this year, although it's still a little bit early to talk.
The intensity that we might end up seeing back to back unusually wet winters in California and parts of the lower Colorado, which we have not seen in quite some time. Okay. Got me thinking back to now. You know, this recent winter that we had here, what were predictions for snow and precipitation and atmospheric river events going into this past winter?
And then I believe and I've saw some reports of there were 31 atmospheric river events or is actually a river is a is a small is a relatively narrow but intense moisture plume that comes in. But where were the forecasts versus reality going into this winter? Yeah, I will emphasize that there were more like 15 or 16 atmospheric rivers in California.
I think the 31 numbers for all of the West Coast that's out of Denver for California. Yeah, my fault in that one. Sorry. Not no worries. Well, so the seasonal prediction for California this past season was, as has been the topic of discussion was where a slight tilt in the odds towards drier than average conditions because of the moderate to almost strong and and persistent third year persistence of La Nina.
Now obviously that didn't happen. But if you look if you look at the large scale atmospheric pattern, though, it's kind of interesting. So the reason why there's a slight tilt in the odds towards drier than average conditions during a significant linear event is because it tends to favor a strong ridge of high pressure somewhere over the Gulf of Alaska, as it turned out, that did actually happen.
There was a seasonally persistent ridge in the Gulf of Alaska. But the problem or maybe the the the saving grace for California was that it was slightly farther to the west and the typical position of the La Nina Ridge. And so instead of blocking storms from making it to California and dropping rainfall and snowfall, it actually was far enough to the west that the return southward flow on the eastern flank of that high pressure system injected a bunch of cold air and atmospheric instability into the mix and helped juice up these subtropical moisture plumes, producing a bunch of atmospheric river storms and a persistent stream of significant storminess all winter long.
So physically, you know, the high pressure system that's connected with cool temperatures in the eastern tropical Pacific essentially happened. But something else occurred that shifted it a little further west than had been initially anticipated. And that resulted in an enormous difference for California, an exceptionally wet winter in some places instead of a drier than average winter. This was something I actually talked about in a blog post back in the autumn last year, which is that, you know, the problem with La Nina and the reason why this linear correlation is not so great is because if you tried to linear correlate La Nina with the ridge in the Gulf of Alaska, there'd be a very strong
correlation. But the problem is the relationship between that ridge in California, precipitation is very tenuous. We're kind of on the razor's edge. If it's far enough to the east. We we are warm and dry in the winter, but if it's far enough west, it's literally the opposite surface condition that's cold and wet because of the direction that the winds end up coming from.
So that's the hard part, is getting the exact longitude of that big ridge correct months in advance. So you can't just say there'll be a big red blob somewhere in the Gulf of Alaska. You need to be able to say exactly where it is, because if you're off by even 500 or 800 miles, which is not a very big margin on the global planetary climate, seasonal prediction scale, you get the completely wrong outcome for California.
And I think that's what happened this year where that ridge was just too far west and we were on the other side of that razor's edge in California on the cool and one side. This year, as is true with much of meteorology, little differences add up and can we do some big changes in the ultimate outcome? One thing I want to look ahead to, you know what has been again until this winter and all the snow and the atmospheric river events, you know, besides the drought in the west.
The other thing that got a lot of attention in the West was wildfire season. How these wildfire seasons seem to be keep getting worse with very little fluctuation. So I kind of want to look ahead to this wildfire season as we get through the summer and things quiet down and get into the fall. What are you thinking as far as wildfires go in the West?
This year is a complicated picture this year because there's as you mentioned earlier, there are actually patches of drought that have gotten worse this winter, despite the rapid improvement in the California Colorado basin. The Pacific Northwest, for example, is headed for a significant drought right now. So we might actually see a were a relatively worse fire season in the Pacific Northwest later this year than than in some other places.
The other thing is that even within California, for example, there's great complexity. So we have such a large snowpack that I think the high elevation fire season this year in California and throughout most of the West, fortunately will be pretty mild because literally there is snow on the ground. It's impossible to have wildfires of any real magnitude right now.
And that might still be the case for a few more months. So by the time August gets around, the snowpack is finally melting away. Well, you don't have snow on the ground anymore, but now you have all this residual soil moisture. So everything is going to be pretty damp up at high elevations. I don't think we're going to see and this has been a real, really big problem in recent years.
We have seen very high elevation, high intensity wildfires which were historically rare and have recently become much more common. I don't think we'll see that this year in places that have a really exceptional snowpack. So that's some good news, a place where I think there will be a mitigated fire season up above seven, eight, 9000 feet. Of course, there's a lot of territory in the West.
In fact, the vast majority of the West is below that elevation. So what happens there? Well, it depends a bit on the ecosystem type. It's actually the case in a lot of the West. The wet years tend to be worse. Fire years historically, because what it means is you have a lot of extra growth of brush and grass.
So if you're in the desert, if you're in grasslands or in sort of mixed trees and brush and grass woodland kind of regimes, you usually get worse for areas after wet winters because you have so much more fuel to burn. That's because these these are regimes that are actually known as fuel limited, meaning that the reason why you don't have more and more widespread and more intense fires is usually because there isn't enough vegetation to burn on average.
Well, these are the years where there is enough vegetation to burn because you've grown extra because there's so much more water than usual. So all of that greenery you're seeing now, lower elevations will become eventually fuel for fires later in the season. And so there's also this interesting dynamic where in places like California, where there were severe windstorms and snowstorms and these no middle elevation zones this winter, there's a lot of trees and branches that came down which are going to end up essentially forming additional fuel for fires later this season as well, along with all that extra brush and grass growth.
So this could be a year where if we do get significant wind or heat or events at the end of the season, we could see a pretty serious failure in certain lower elevation zones, but a really mild failure at higher elevations. And so I think there's both geographic variation where the Pacific Northwest is actually pretty dry right now, but the Pacific Southwest is pretty wet.
And there's also a elevational dependance for places that had a big snowpack right now probably aren't going to have much of a fire season this year, but the lower elevations might see potentially a elevated fire season in some places, depending on how things go. Yeah, that's really the irony of the whole bit, to be sure. Before we let you go, I do want to talk a little bit more about atmospheric rivers.
I think that term has really jumped into the lexicon over the last 5 to 10 years, especially in the West. What do we know about atmospheric rivers and and the warming climate in general? Yeah, So there's a strong consensus at this point in the scientific literature that the strongest atmospheric rivers will become considerably stronger moisture and produce more intense precipitation than a warming climate.
Interestingly, there's less consensus about what happens on average to the frequency of atmospheric rivers overall. So really the strongest argument that we can say is that really throughout western North America, where our rivers are relevant, that the most extreme atmospheric rivers in a warming climate will be significantly wetter and will pose significantly greater flood risks. But doesn't necessarily mean we're going to see more atmospheric rivers overall.
In fact, we may even see in some places like California, more variable city of atmospheric rivers from year to year. Rather, the wet years are really wet, increasingly so. And as I mentioned earlier, the dry years or perhaps even drier, you know, this really comes down once again to basic thermodynamics. As you mentioned, atmospheric rivers are at their core.
These concentrated plumes of atmospheric water vapor, long but narrow, pushed by strong winds over your head. They can they can carry volumes of water that are many times that of the Mississippi River in flood, but in the form of vapor over your head. So these are huge amounts of water volume that we're talking about. And you can imagine that in a warming climate where the water vapor holding capacity of the atmosphere increases exponentially for each linear increment of warming.
So in other words, this is about 7%, four centigrade degree centigrade or about 4% per degree Fahrenheit of warming, that atmospheric sponginess increases by either 4% per Fahrenheit or 7% per degrees Celsius. You know, that would be a pretty darn good interest compound interest rate in a bank. If you get a47 percent guaranteed return. I think anybody would be excited about that.
But it's a little bit scary you we talk about it in the context of the ceiling on extreme precipitation, which by our best estimates does increased by about 4 to 7% or Fahrenheit or Celsius degree of warming. And globally, we're already at 1.2 or so degrees Celsius of warming, getting close to two degrees Fahrenheit of warming locally in California during, you know, in some places we're already higher than that because, you know, the land is warming faster than the ocean.
So this is not an insignificant change. Yeah, for sure. And I think that's one of the things that I think all of us as scientists and media that's meteorology or climate science, I think a lot of people understand outside of the scientific disciplines that, yeah, if it's warmer, you can evaporate more. I think a lot of that's intuitive, but I'm with you.
I don't think people understand that it's not linear. It goes up dramatically as you get warmer so that when we do have these higher end events, they are so much worse. Daniel, we're going to cut you loose. We appreciate you joining us. An addition to the Twitter and YouTube. Where else can people find out about the work you do?
Well, I do also write the weather blog. You can find that at Weather West Tor.com. As you mentioned, you know, I try and spread my my public facing science communication across these platforms, Twitter, YouTube and my own weather. WESTCOTT So and, you know, I like to join other people's podcasts on a pretty regular basis, too, So you can find me here, there and everywhere, I guess.
DANIEL Terrific. Thanks again so much. I know you're busy. It has been a wild, wild winter and early spring and now mid-spring. There in the western United States. So we hope to talk to you again real soon. Thank you so much for joining us. Thanks again for having me. I'll be right back with a few closing thoughts on the across the podcast.
And we're back with some closing thoughts on the Across the Sky podcast. And meteorologist Sean Sublette of the Richmond Times Dispatch, along with Matt Hollander in Chicago and Joe Martucci at the Jersey Shore, the press of Atlantic City. And Daniel, guys, he is just he has such a deep understanding of the weather patterns there. We kind of forget about how volatile it can be in the western United States.
We've all kind of, you know, got locked into this idea, well, it's dry and it rains on occasion and they're in trouble. They're running out of water. And then you have a winter like they just had. They're in the western United States. And it really reminds you just how volatile can be. You know, they don't have tornadoes and like we have east of the Rockies, but they had their own entire set of issues, that is for sure.
Yeah. And he did explain all the intricacies of water and making sure there's enough water for everybody. I mean, one thing that stuck out was how much So that land has been sinking in the valley just through pumping out the aquifers. I think I've even seen a couple of photos online of like these huge rollers. If you guys ever seen these, like these huge rulers of like tens of feet about how much actually the land has sunk over the past couple of decades.
So and the other thing is to, you know, one of these really wet winters is good, still a long way to go to being really on top of it there. And we get throw in the climate change factor. And I like to say it's a lot of time the people do. It's not so much you're just over one.
We're more variable in our weather events. And when it comes to Western water management, that's something that. It's just getting, I believe, harder for our water managers to, you know, taking control in terms of these forecasts because we do have, you know, hey, we had a extremely wet winter this past winter, is it? Daniel said he's trending towards having another one of these kind of winters as we go into next winter.
Good news. In the short term, we have to see what it means. Well, the other thing that stands out to me is just how the atmosphere is becoming more extreme. You know, we were dealing with the extreme drought and then quickly switched and remarkably, how quickly we switched to extreme rain and flooding. And that's just what we're seeing with climate change is how the extreme nature of these events, these extreme events are happening more frequently.
I mean, you can talk about, you know, it goes with other areas, too. You know, when you're looking at, you know, the intensity of hurricanes, for example, there's some uncertainty in the exact number of hurricanes and how that's going to change with climate change. But what there is a clear trend towards is an increase in intense hurricanes and increase, as Daniel referred to.
You know, it's still uncertain exactly the number of atmospheric rivers that we're going to see. But when there is an atmospheric river, it's more likely to be an extreme atmospheric river. When we have a drought, it's more likely to be an extreme drought. So there's going to be fluctuations. It doesn't mean like the West is always going to have droughts or it's always going to flood.
You know, it's more complex than that. But what we are clearly seeing is a trend in these more extreme events, which is the most high impact from an economic standpoint, you know, and the toll that it takes on people. So, gosh, just, you know, that's that's what really stands out to me is just how many extreme events and not just in the West but across the planet.
Yeah. I mean, we've always known that that part of the United States has very highly variable weather to begin with, and they're kind of susceptible to dry and wet periods. But I think that Daniel's point is that we're really seeing that ratcheted up even further. And, you know, we try to remind people it doesn't all just balance out because the evaporation rates are so much higher in a warming climate so that the ground dries out faster.
And if you have heavy rain on dry ground, there's more running off than it would be if the ground was a little bit moist, kind of like, you know, you turn the spigot on on top of a wet sponge versus a dry sponge, you get two very, very different impacts from that. So it is going to be quite a quite a challenge for water management, certainly in the western United States for decades and decades to come.
With that, we're going to close it up for this week. We do have a few more things kind of percolating in the weeks to come. We've had the aurora borealis show up, so we're kind of working on a couple of things there. We hope to have some news on that coming up soon. But right now for Matt Holiner in Chicago, Joe Martucci, Atlantic City and Kira Saline and Tulsa, our meteorologist Sean Sublette.
And we will see you next time on the Across the Sky podcast.See omnystudio.com/listener for privacy information.