UCLA researchers say California is overdue for a megaflood that would effectively turn the state into a "vast inland sea." Climate change isn't helping this inevitability.
Few people associate urban and suburban Southern California with floods anymore, mostly because many of its rivers were dammed up or transformed into concrete gulches long ago. But scientists say a megaflood could hit the entire state and would submerge cities, hitting communities of color particularly hard.
The state is nowhere near prepared for that. Today, our Masters of Disasters talk about this upcoming flood, what it could mean for a rising sea and more. Read the full transcript here.
Host: Gustavo Arellano
Guests: L.A. Times earthquake-COVID reporter Ron Lin, L.A. Times coastal reporter Rosanna Xia, and L.A. Times environmental reporter Louis Sahagún
More reading:
Major flood would hit Los Angeles Black communities disproportionately hard, study finds
Risk of catastrophic California ‘megaflood’ has doubled due to global warming, researchers say
More than 400 toxic sites in California are at risk of flooding from sea level rise
Gustavo: It's a natural disaster of biblical proportions. Noah, get that ark.
Floods, the unstoppable force that moves immovable objects and who makes them worse? Humans. Poor planning and infrastructure have caused unnecessary billions of dollars in damages, which too often hits the poor and people of color the worst.
Here in Southern California, where we turned most of our rivers into concrete gulches long ago, floods seem as unlikely as Gavin Newsom becoming governor of Texas.
But now UCLA scientists (go Bruins!) are saying that California is overdue for a megaflood that would turn the state into a “vast inland sea.” Get those oars ready, folks, because we're all going to have to row, row, row our boats somewhere, anywhere out of here.
I'm Gustavo Arellano. You're listening to The Times: Essential News from the L.A. Times. It's Wednesday, Nov. 30, 2022.
Today, are we in California prepared for the next big flood or even a small one? What can we learn from history, and why in this new age of extreme weather are floods going to become even more common and bigger than ever?
It's times like these that we turn to my colleagues of catastrophes, our mariners of madness, the admirals of aaaaaah!, who steer ships in the choppiest of seas. Oh, captains. My captains. Yes, it's time for: Masters of disasters.
Musica, maestro.
Sitting as always in the earthquake chair is Ron Lin. So Ron: Earthquake or flood, which are you more scared of?
Ron: Always the earthquake, but the flood would be a close second because probably I won't ever expect it.
Gustavo: Oh my God, well. Always has to stick with the earthquakes. Joining us is our Cassandra of the coast, Rosanna Xia. Rosa, if she sells seashells by the seashore, does he hawk Seahawks by the Bayshore?
Rosanna: [laughter] Gustavo, I’ve got nothing for you on that one.
Gustavo: I have finally trumped the master comedian, Rosanna. Yay me. And finally, a big welcome to Louis Sahagún, our master of masters: environment, animals, water, and so much more. Louis does a bear write in the woods?
Louis: You know, uh, my answer to that is hang on to your pool toys, cause you're gonna need 'em pretty soon.
Gustavo: Already set on the floods. Who cares about the bears? The bears are gonna beat us all anyways. Masters, welcome. And we're gonna start with Louis, cause I know that when we talk about water disasters in Los Angeles, nowadays we're talking about a lack of water – because no more rain anymore. But Louis, you've written about the great flood of 1862, the largest recorded flood in the history of California, Nevada and Oregon. What on earth happened back then?
Louis: Thirty consecutive days of rain triggered a flood that turned all Central California into a lake that could only be crossed by a boat. And it changed the course of the L.A. River, such that the mouth shifted from Venice to Long Beach. More floods like that are going to be coming more often. In fact, scientists say that the chances of another flood of that scale have jumped from 1% in any given year to 2% in any given year because of climate change.
Gustavo: Oy veh. And didn't they give it like, some nickname, like, the ARkStorm or something?
Louis: Yeah that's a title that was given, uh, this scale of impending flood by the U.S. Geological Survey. And the ARkStorm would be greater than that flood of 1862. But if it happened today, the damage, the chaos, the death would be far, far greater. They are saying that another flood like that in California would cause $1 trillion in damage, which would be larger than any catastrophe in recorded history, and I'm sorry, Ron, but earthquakes would be – run a distant second.
Ron: You're totally right.
Gustavo: Oy veh. And if that happens, not only that, Rosanna, but then coming in from the Pacific is rising sea levels. So what does a one-two combo like epic floods and rising seas do for coastal communities?
Rosanna: Yeah, where do I start? So the first thing I'll say is when I hear about the extreme, extreme floods Louis is talking about, that's a sudden, immense rush of water from the sky, from swollen lakes and rivers that's trying to get to the ocean as fast as it can. So what happens when the ocean is also rising, you know, at a high tide, in El Niño or mega storm surge and the water from the ocean is also trying to push into the shore? That's a lot of water, with nowhere to go and a lot of communities and people and infrastructure in the way. And so the numbers keep changing on sea level rise, but the research has increasingly focused on what they call combined risk events. So it's not just looking at sea level rise on its own, it's looking at how does that sync up with El Niños and expected extreme precipitation and the flood scenarios that Louis has written so much about. And you know, as of now, officials across California have committed on just the sea level rise front to preparing the state for at least three and a half feet of sea level rise by 2050. That's less than 30 years from now, and at least $8 billion in property in California could be underwater by 2050 based on recent studies. Not $1 trillion kind of in what Louis just outlined, but $8 billion is still pretty remarkable if you think about how built out our infrastructure is along the coast. Studies are saying that an additional $10 billion is at risk during high tides on top of the projected sea level rise.
Gustavo: The scariest thing about all of this, there's a saying that plumbers say: water finds a way. So Ron, humans have tried to channel that water and so long ago, built all sorts of concrete canals to divert the rainwater, the floodwater, possibly into the ocean. How do they work?
Ron: Yeah, so you know, we've seen this all over the state. Human engineering is needed to evacuate water as quickly as possible to the ocean. And so in places like the L.A. Basin and the Central Valley, it was westerners who decided to build cities where floodwaters were common. So in L.A. there would be these floods that would continue happening. And then finally in the thirties, there was a decision made to build dams and line the L.A. River and other rivers with concrete, with the goal to hold back excessive water during heavy rains, you know, behind dams. And then the concrete along the rivers quickly dispatches us out to the sea. Not only was this an L.A. thing, it was a thing up in the Sacramento Valley. And Sacramento, for example, it's built where the Sacramento and American rivers meet. This was not an issue when Indigenous peoples were the main population centers. But it is an issue when there were fixed cities. So a key strategy in the Sacramento Valley is to set aside vast plains of farmland that connect as a kind of a flood superhighway that sends excess water traffic towards San Francisco Bay. In fact, back in 2017 there was so much rain that fell that the Yolo Bypass was filled with water. This is basically farmland that is designated to be an inland sea, and you can see it when you’re, uh, on Interstate 80 west of Sacramento, when you're driving over it, most of the time it's just farmland. But during this period of time, it was filled with water.
Rosanna: And just to chime in here for a second, I mean, I, when you said water finds a way, that just reminded me that it is important to note that because we have lined our rivers with concrete and also paved over much of the floodplain with roads and neighborhoods and homes. I mean, historically, if we weren't building on top of all these systems and landscapes, the water would be absorbed by the riverbed or in the wetlands, and all of that has kind of been altered, filled, paved over for our built environment. So water really doesn't have a place to go, and I think that's still important to note as well. There were natural systems within the floodplain, coastal floodplain, for this water to go somewhere.
Louis: Actually, since water flows downhill, it's going to flow right into low-lying minority communities, Black, Latino and Asian. And it's gonna fill 'em up like bathtubs because that's where they were relegated to due to redlining since World War II.
Gustavo: We'll be right back.
Gustavo: Louis, when it rains, it pours. When it pours, it floods. And when it floods, it gets really messy. We've talked about this before on the podcast. What do you call mudslides again, Rosanna?
Rosanna: Debris flows.
Gustavo: Oh yeah, mudslides, debris flows, same difference… anyway. Anyway, Louis…
Rosanna: Boo.
Gustavo: So we always hear in SoCal, Louis, after a rain to stay out of the ocean for at least three days because the toxin levels at the beach are so high. But you mentioned earlier, I could only imagine if flood hits people's neighborhoods and homes, how they're gonna be left. So what did the scientists that you talked to for their studies say about who is gonna be affected by all this extra flooding?
Louis: You know, as bad as a flood can seem and is from the surface, under the surface, it's a murkier story.
You're looking at chemical depots that were knocked down by the flooding and released their toxic chemicals into streets and homes. That, when you see people sloshing through neighborhood streets, streets turned to rivers, for example, on news coverage, you don't realize that they're moving through deadly chemicals more often than not. And above the surface of those flood waters is toxic chemicals filling the air that they're breathing.
Gustavo: Yeah, scary. We talked about it with tsunamis, but if it floods, folks, we have a solution: The government has come to save us. For people who need to be warned about flooding, there's a flash flood warning that appears on cellphones.
Aoooga aooooga. Ron, how effective has this emergency system been?
Ron: Well, there have been problems over the years from decisions not to issue an alert. But then, just on election day there was actually a flash flood warning that was intended to just hit a small section of the county, east of Duarte. Instead, it went out to the entire, all of L.A. County. I even got it up here in the Bay Area cause I'm tied up in the system. So we know that the system can work, but it still seems like they need to find a way to fine-tune it a little.
Louis: You know, warning is one thing, so most people are gonna get the warning, you know, however sophisticated that system is. But often forgotten about and not dealt with is disaster recovery, which takes longer for poor folks because disaster recovery programs favor affluent communities. And that needs some work.
Rosanna: Yeah, and we see that often in just the hurricane-hit states on the Gulf Coast. I mean, that just played out this summer.
Ron: And the other thing I think to to think about is that, you know, when you get an alert saying, flash flood warning, what does it mean to most people? I think they would just think, you know, they might shrug their shoulders and think, oh, it's gonna rain. But there are real implications like, just near from where I live in Millbury in San Mateo County and just in one of the more recent rainstorms, there was a flood that hit an underpass and two motorists died from floodwaters and it had never happened before. And part of this has to do with infrastructure. It was an underpass built so that it could go underneath a railroad crossing. But we are getting these kind of intense rainstorms, that seemingly are not something that we've had in our lifetime. And I think it's super important for people to realize that the decades or the generations where flooding hasn't been a problem are, are ending.
Gustavo: Louis, how have government officials responded to recent major floods in California?
Louis: Government officials are concerned, but here is something that no one's talking about and they should be. No county, not even a state, not even federal EPA has the kind of sophisticated monitoring devices and capabilities that NASA does. And so when we have a major flood – be it in Houston, be it in New Orleans, maybe in L.A. one of these days – NASA should be part of the response. They have the equipment, they have the satellites, the planes outfitted with systems that are far more advanced so that we can get a better sense, specific sense of where the dangers lie. In the air, in the water. Under the water.
Gustavo: Yeah NASA, forget about Mars. Focus on the freaking coast.
Louis: Ha. Yeah.
Gustavo: Rosanna. Uh, Seriously. I feel in this episode you're even more doomy than usual because Louis comes in with the flooding and the coast is like, hold my flip-flops. I got just as bad news for folks. You've written about how so-called toxic tides are also affecting communities of color. What on earth are those?
Rosanna: Yeah, I mean it's terrifying just hearing Ron and Louis talk the specifics of these shorter term, extreme flood risks. But when I think about flooding, especially along the coast in California, I think about all the flood risks that aren't as in your face. You know, when people talk about sea level rise in California, you hear a lot of talk about building more sea walls and protecting homes in Malibu from falling into the ocean. But less talked about is all the power plants, the factories, the refineries, the toxic dump sites right on the coast that could also flood as the ocean rises. And historically, guess what? Our land use patterns have unfairly placed the burden of industrialization on lower-income communities of color, as Louis spoke to earlier, and researchers at UC Berkeley, and UCLA, and you know across the nation, really homed in on how the intersection of our redlining practices, our historic discriminatory land use practices intersect with who is now disproportionately burdened with these risks. So, a study called Toxic Tides that you alluded to, Gustavo, recently found that Black and brown communities in California are actually five times more likely to live within half a mile of an industrialized, often toxic site that could flood in the coming decades. And there are hundreds and hundreds of these toxic sites along just the coast of California and likely more than a thousand just along the Bay Area shoreline alone. And they're often in communities that have been largely overlooked. And the other thing that really haunts me when it comes to flooding on the coast is this less talked-about threat of groundwater. Not our drinking groundwater, hundreds and hundreds of feet underground in confined aquifers, but the shallow groundwater that is sitting like less than 10 feet beneath our feet.
This groundwater gets pushed up towards the surface as the ocean rises and pushes inland. And when this groundwater breaks the surface, it also causes flooding issues and has the potential to remobilize contaminated soil, even Superfund sites that had been supposedly buried or capped. And the health risks here are huge, and no sea wall can stop this kind of flooding from the water beneath us. And there are no clear answers to this issue but this is kind of element of the flood discourse that is really coming to a lot more people's attention.
Gustavo: Oy veh. I’d hope with terrible things like that, that the government would try to do more to prevent stuff like this from happening, you know?
Rosanna: When I speak to communities that have been waiting for decades for a Superfund site down the street to be cleaned up, I mean it, it takes one flood to really cause a lot of devastation and we shouldn't wait for that flood to happen in order to do something about it. I mean, we tend to say that the response happens after the disaster, but some communities can't afford to wait until that disaster happens.
Gustavo: So is there anything people can do to prepare for a flood? Uh, we’ll start with Louis.
Louis: Uh, yeah. Buy an inflatable raft.
Gustavo: Oh boy. OK. How about, uh, life jackets maybe too?
Louis: You know, I'm only half kidding, but here's why, uh, with regard, for example, L.A. County and the poor communities that are going to get hit hardest. All right, so what are the alternatives for those people? Well, they might be raising those homes, many of them built 100 years ago. But oh, it costs one- to $200,000 per home to lift it three feet. It costs about 10 to 15, 20 thousand dollars to raise their electrical outlets three feet or more. So since these are the poorest among us, who's gonna help them? It won't be easy.
Gustavo: Rick Caruso, come on down. Ron, how can we prepare for a flood?
Ron: Some common-sense things that I think are super important is that, you know, especially if you live on a hillside or anything, you know, when a big storm is coming, you know, we often get advance notice of those, you know, look out on your street, look, see if those storm gutters are clear of debris. You know, you can be part of your helping to save your community behind that. The other thing you can look at is, wherever you live, you know, check out to see what kind of dam is behind you. I think that'll help better prepare you psychologically for what might happen if flood waters do come.
Gustavo: Rosanna, do you know your local dam?
Rosanna: I do. I'll also just say, I think awareness is step one to preparedness, just understanding and being aware that it does flood in Los Angeles because every time it rains in Los Angeles, it's like no one – just looking at how people drive, I have no hope on how people would be able to respond to a flood. So I think really kind of understanding that.
Gustavo: Oh my God. If our masters do not have any hope, we are truly, truly doomed. But can't we invest in boats?
Rosanna: I just, I mean, I would just say one thing to remember is to not underestimate how fast the water moves and how heavy the water can be and you just don't wanna be trapped in that. But, you know, flooding from sea level rise is a slow moving disaster that over time really adds up to a whole lot. And so a question that has been emerging in this space is the question of frequency. Like how often does a home or a road on the coast have to kind of flood a few times per year to essentially be underwater?
I do think another call to action here is to really not only think about what it means to prepare for the big floods, but also to be thinking more consistently about what it means to be constantly kind of underwater. And what kind of policies or decision making we would need to really rethink our relationship with water? And that would be a good question to ask yourself and your elected officials as a way to start preparing for the longer-term, slower-moving disaster pushing onto our shores.
Gustavo: Noah, where's our ark? We'll be right back.
Gustavo: And now comes our traditional ending to Masters of Disasters, where we ask our masters what's bringing them joy during these terrible, doomy times. Ron, let's start with you. What's bringing you joy this month?
Ron: Uh, veterinarians. Our rabbit Jewel –
Rosanna: No, what happened to Jewel!
Ron: – had a series of health issues –
Gustavo: Jewel has to live!
Ron: – including a urinary tract infection, and lately she was found to have had a pretty good-sized bladder stone. But just, yeah. But just a few minutes ago we heard the surgery was successful and uh, she should be right as new.
Rosanna: Long live Jewel!
Gustavo: Long live Jewel! Because it's like Nietzsche said, without Jewel, anything is possible. Louis, what's bringing you joy?
Louis: Uh, playing blues guitar with one, perhaps two cold beers.
Gustavo: Oh, that's a good one. T-Bone Walker or, uh, Robert Johnson?
Louis: Both.
Gustavo: That's a good master right there. And Rosanna, finally, but not leastly of course, what's bringing you joy this time?
Rosanna: Yeah, I mean this might sound silly, but I've, I've been trying to compliment people more regularly, kind of like the daily gratitude exercise, except the question I ask myself is, who have you complimented today? And there are just so many people out there and in our own newsroom doing great work that just feels so increasingly thankless. And I'm also guilty of being too busy to stop and actually pass on a compliment, even though I might be reading an article and thinking “This is amazing,” or “Oh my God, this person just completely changed the way I thought about” X, Y, Z issue. But yeah, thinking and complimenting people more often has helped me remember lately that this world isn't just a bunch of people yelling at you on the internet all the time. And that has brought me a lot of joy.
Gustavo: But have you complimented yourself recently?
Rosanna: No.
Gustavo: Well you should, because, Rosanna…
Rosanna: I don't count.
Gustavo: You are awesome. All the masters are awesome. That's why they’re our…
Masters of Disasters. Ron Lin covers earthquakes and pandemics. Rosanna Xia covers the coast and Louis Sahagún covers it all. Thank you, all my masters.
Rosanna: Thank you.
Ron: Thanks so much.
Louis: Thanks. Take it easy.
Gustavo: And that’s it for this episode of The Times: Essential news from the L.A. Times. Denise Guerra and David Toledo were the jefes on this episode. Heba Elorbany edited it and Mark Nieto mixed and mastered it.
Our show is produced by Shannon Lin, Denise Guerra, Kasia Broussalian, David Toledo and Ashlea Brown. Our editorial assistants are Roberto Reyes and Nicolas Perez. Our engineers are Mario Diaz, Mark Nieto and Mike Heflin. Our editor is Kinsee Morlan. Our executive producers are Jazmín Aguilera, Shani Hilton and Heba Elorbany. And our theme music is by Andrew Eapen.
I'm Gustavo Arellano. We'll be back Friday with all the news and desmadre. Gracias.