Unexplainable - Who's afraid of big, bad Yellowstone?

Episode Date: January 5, 2026

Yellowstone can be a deadly place... but not for the reasons you might think. Guest: Mike Poland, scientist in charge at the Yellowstone Volcano Observatory For show transcripts, go to ⁠⁠��⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠vox.com/unxtranscripts⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠ For more, go to ⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠vox.com/unexplainable⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠ And please email us! ⁠⁠⁠⁠[e-mail]⁠⁠⁠⁠. We read every email Support Unexplainable (and get ad-free episodes) by becoming a Vox Member today: ⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠vox.com/members⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠ Thank you! Learn more about your ad choices. Visit podcastchoices.com/adchoices

Hey, I'm Matt Bouchelle, comedian, writer, and floating head you may or may not have seen on your FYP. And I'm starting a brand new podcast. Wait, don't swipe away. It's called, That Sounds Like a Lot. You know that feeling when you check your phone, read a few headlines and think, that sounds like a lot. I can't do this. Well, I can, and I'm going to get into it every Friday. You can watch on YouTube or listen wherever you get your podcast. I'm going to start by breaking down whatever insanity is happening in the world. And then I'll sit down with a comedian or actor or writer or, honestly, anyone who responds to my DMs. This is not the place to get the news, but it is a place to get the news.

but it is a place to feel a little bit better about it. That sounds like a lot coming May 1st, part of the Vox Media Podcast Network. When I was a kid, I remember hearing about Yellowstone. I remember hearing that it was a national park, that it had a big volcanic system with lots of geysers, and I remember hearing this really scary story about it. A story that Mike Poland, the scientist in charge of the Yellowstone Volcano Observatory, basically knows by heart.

He hears versions of it, all that. the time. You would have heard that Yellowstone has had incomprehensibly big eruptions. Yes. And this is true. You may also have heard that Yellowstone is brewing and stirring away and one day is going to have another one of these eruptions and we don't know when. It could be tomorrow. And if it does that, then it could mean the end of the human race. I may be pushing things a little far. I hear that a lot. And these things just aren't, they just aren't true. I'll be honest, this was news to me. I called up Mike to ask him, what's the deal with Yellowstone?

Right? Like, will there be an eruption any day? Why don't we know? Et cetera. And instead, he told me that there is a lot that we don't know about predicting volcanoes. Like, we wound up doing a whole episode on just that subject. But when it comes to Yellowstone specifically and irrepressurember, in the near future, scientists like Mike have a lot of confidence.

We can look at what's happening beneath the surface and understand whether or not we're brewing, we're getting ready for an eruption. And we know that's not the case at Yellowstone. So Yellowstone is not a threat in terms of volcanic activity in the immediate future. So this is unexplainable. I'm Bird Pinkerton. And today on the show, why Mike is so confident that at least in this one respect, the Yellowstone system is pretty explainable.

But also, Mike will tell us some mysteries about Yellowstone that he would like to solve. So if it's not true that Yellowstone is going to erupt imminently or could erupt at any time, where did that idea come from in the first place? So the discovery of Yellowstone as a really, really massive volcanic system was really kind of late 50s, early 60s, when geologists started looking at the region and understanding the rocks that were there. It had been known to be a volcanic region for a long time. Then geologists started to identify the rocks,

started to become more familiar with the rocks in the area, and realized that some of the rocks they were seeing weren't lava flows. It was compressed ash. And all of this started to sort of come together as a story that Yellowstone has had some really, really big eruptions. The ash was so thick that it well, It was welded itself together.

It became incredibly dense. And it would have swept across the landscape for, who knows, 100 miles, something like that, from its source, just sort of sweeping the area clean. These were really, really big eruptions that also would have had an impact on climate because they would have put a tremendous amount of ash into the atmosphere that would have reflected sunlight and caused some cooling. And so that's a fantastic story. Will that happen again one day? Maybe.

It's hard to tell. And if it does happen in the future, none of us that are on Earth now are going to be around to be able to know whether or not it happened, right? So in some ways, I find it kind of a funny question. Mike told me there are a couple things that make him so confident here. One is just looking at Yellowstone's geological record.

This is not something that's going off all the time. You walk into the Yellowstone landscape, and it doesn't look like Hawaii where there's nothing growing because these lava flows are so recent. Clearly, the stuff that had come out was relatively old. That doesn't mean it's inactive. It doesn't mean it won't happen again at some point in the future.

It will have episodes of lava flows that may occur, but the last one of those was 70,000 years ago. It can have really massive explosions, maybe once every million years, maybe slightly less than that. But it is clear that this system was not just constantly going off all the time, that there were long pauses between eruptions. So we appear to be in one of those periods of quiet, not in the middle of these episodes of volcanism. And the geological record also holds clues to help us understand when we might need to start worrying. So, for example, if you look at old lava from Yellowstone,

it's apparently full of tiny crystals. Those crystals grew back when the lava was magma, so inside the earth. And they grew in layers. You can think of them almost like tree ring layers. And just like tree ring layers can tell you stuff about bygone weather or bygone water levels, the layers on these volcanic crystals record moments of intense heat down in the magma chamber, for example. So we can use the crystals as a clue of what the magma chamber might have looked like through time. And what we generally see is that there is some sort of like thermal event, like a heating event prior to eruptions.

It makes sense, right? Right. Like you would, it would make sense that you'd be like, oh, right before there was an eruption, things got hot. Yeah, things got kicked up. Things got jumpstarted. And apparently, volcanologists can monitor a system like Yellowstone to see if that's happening currently, to see if heat is coming in to jumpstart an eruption in this way. You can basically do something that's akin to like taking an MRI of the Earth. You can do that with magnetic and gravity. The most common way to do it was seismic waves. So as seismic waves pass through the earth, if they encounter something hot and maybe partially molten,

they're going to slow down. Okay. And if they hit something really solid and cold, they're going to speed up. And we can measure the travel times of seismic waves as they pass through the subsurface and we can put a map together of how fast things are moving through the subsurface.

When they peered down, down under Yellowstone, they can see that it's definitely hot down there, but not so hot that they anticipate a super volcanic eruption. Essentially, it's not melted enough. Imagine a lava cake that is like, I don't know, 10 years old. And, you know, a lot of that chocolate just is not flowing anymore. There might be some pieces that are still, you know, maybe not 10 years old. Maybe 10 is a bit much. But maybe it's a week old cake words.

Maybe it's a week old, right. And so when you slice into it, you know, nothing moves. There's no flowage there because it's, you know, 80% solid. Now, if you took Yellowstone and injected a lot of heat somehow, if magma came up from below to heat up the whole system, it would be like putting your lava cake back in the oven. That would melt that gooey center and you'd be back to having your lava cake. that's maybe a good analogy for Yellowstone. We haven't seen that rejuvenation event. We're dealing with a system that is, you know, a couple-week-old lava cake.

And this couple weeks old lava cake is just probably not going to end the world in a fiery nightmare of ash and lava. And so this is why Mike is so prepared to allay people's concerns on this one. Based on all the information that he and his fellow volcanologists have at their disposal, he really does think we can check death by a super volcanic. Yellowstone Explosion off of our list of imminent apocalypse scenarios. But before you breathe too easily, there are still lots of other ways for Yellowstone to kill you. It's all about you. And when you fly with Virgin Atlantic in their upper class cabin, they take the VIP treatment to the next level. With a private wing to check in and your own security channel

at London Heathrow, you can glide from your car to their clubhouse, a destination in its own right in 10 minutes or less. On board, you can treat yourself to your own private suite to stretch out in, with lots of storage space, a lie flat bed, and delicious dining from beginning to end. Just be sure to leave room for dessert. Their mile high tea with all the little cakes and sandwiches is a showstopper. Go to virginatlantic.com to learn more. I'm Maria Sharpova, and I'm hosting a new podcast called Pretty Tough.

Every week, I'm sitting down with trailblazing women at the top of their game to discuss ambition, work ethic, and the ups and downs that come on the path to achieving greatness. We'll dive into their stories and get valuable insights from top executives, actors, entrepreneurs, and other individuals who have inspired me so much in my own journey. Follow Pretty Tough wherever you get your podcasts. I'm a Sted Hearnden, and this is America, actually. We're all talking to each other to see what did we do wrong? What did we not see? I'm in Washington, D.C. this week to interview Ruben Gai Go. He's a

Democratic Senator from Arizona, and he's been thinking openly about running for higher office. But he's recently run into some hot water because of his connection to Congressman Eric Swalwell. I have to learn from this, and I will learn from this. But for me, it's not a 2028 question. It's about what it means to be a better first boss in my office and also a better senator to my constituents. This week on America, actually, we asked Gallego about predatory behavior in Washington. his plans for immigration reform and more. You come barging in here asking me to contribute money to a volcano relief fund for crack a toll. It was supposed to erupt.

In our conversation about Yellowstone, Mike told me, sure. A volcanic supererruption maybe does not need to keep us up at night. But that doesn't mean that Yellowstone is this totally benign place. There are other hazards that could happen in our lifetime that we might want to think about instead. hazards like, for example. Strong earthquakes. The largest earthquake ever recorded in the Intermountain West was just a few miles west of Yellowstone National Park.

It was a magnitude 7.3 in 1959, and it caused an entire mountainside to collapse. Oh, my God. And that mountainside rushed through a campground at about midnight, and it killed a lot of people, the over two dozen people died. it dammed a river and it created a new lake. And the Army Corps of Engineers and some local folks had to get in there very, very fast and build a temporary spillway. Because if they hadn't done that, the debris dam could have failed catastrophically.

And then you would have had a flood going down this river and then taking up some towns downstream. Oh, my God. That's pretty consequential. So that's hazard number one. The other one, a steam explosion like what was. we saw in July of 24. Wait, what is a steam explosion? So you are dealing with a, at Yellowstone, a very poorly engineered pressure cooker or instapot, or depends on your generation, I suppose, for which analogy you'd want to use. There is a lot of boiling water just beneath the surface.

It is flowing through conduits that are constantly having minerals precipitate out into them, And so they're getting clogged and pressure builds. And that creates a condition where you can have water flashing to steam. And when that happens, you have rapid expansion and kaboom. Taking you to Wyoming now. Yellowstone National Park Rangers closed the Biscuit Basin area today after a hydrothermal explosion. Happened this morning. That's what happened on July 23rd, 2024 at Biscuit Basin.

Only about two and a half miles of so from Old Faithful. There was a really dramatic steam explosion. Sending a black plume of steam and mud up to the sky. No one was injured, fortunately, but there were a lot of people that were in the area and had to run away from rock and mud, boiling water that was flying all over the place. Scientists at Yellowstone tell us that this was a random event without warning. That kind of thing happens almost all the time in Yellowstone. It's annually there are explosions, maybe not that dramatic.

And certainly, that was one of the best viewed ones because it was in the summertime, at a well-visited geyser basin, you know, during the day on a beautiful blue sky day. But that kind of thing has been a hazard we've been trying to emphasize for a long time. And it's a hazard any place, any volcanic carry where you've got a lot of boiling water just beneath the surface. Is that a predict, like, you can't say... Ooh, that's tough. Right. The same way that it's hard to predict when your pressure cooker is going to go off.

Yeah, right. I mean, if your pressure cooker has a crack in it or something, you know, like, is it going to work? Is it not going to work? I don't know. Maybe it'll blow up. Maybe it won't. It's possible that there is some indication. And we just haven't been able to see it yet because we're either not measuring in the right place or we're not looking at the right parameters. So it's possible that there are precursors. We don't know that. Are you trying to figure that out? Yeah. Oh, absolutely. The process for trying to figure out what might trigger a steam explosion involves a bunch of equipment set up to detect and measure things. like low-frequency rumblings or how the ground deforms, so how it swells or shrinks as

as hot rock changes beneath it. They're taking seismic readings as well. All this stuff where the hope is that they could look through this data and say, oh, when there is a lot of rumbling or, say, a lot of deformation that looks like this or looks like that, those tend to be, signs that steam is about to explode. So far, they don't have the steaming gun. But Mike says that might be because their equipment hasn't been close enough to the site of any given explosion. Or he says it's also possible that they just haven't looked at the right data yet. Like maybe as hot water pools just below the surface preparing for a steam explosion, there could be an electrical charge that builds up somehow. So maybe we should be looking at the electrical activity, the conductivity, the resistivity

of the subsurface, basically passing kind of electricity through the subsurface and seeing how well it moves. Or maybe we should be looking at magnetic properties of the materials, which will change depending on how hot it is or how much water is moving around. Or maybe there will be changes in the temperature of the spring. Now, the challenge here is that we don't have many examples. We have any examples where we've been measuring these things at a place that's blown up. Right? Sure, sure. You know, it's almost like a whack-a-mole game, right?

We know biscuit basin blow. Black Diamond Pool and biscuit-Bas-and-Bloop. So we'll go run out there and we'll put a bunch of stuff in area of Black Diamond Pool. And two years from now, some other pool will blow up, right? And then we'll run over there and do some. Why don't you have equipment at every pool? Limited equipment. Yeah, okay.

If I wanted to pay $7 trillion-zillion. and you could put equipment at every pool. Well, but there's also a, there's not just a financial cost to that. There is a cultural cost. I mean, do you want to go to Yellowstone and see wires and solar panels and batteries and all that stuff all over the place? Yes. That's actually my dream. Pave paradise?

Have a parking lot, yeah. At the end of our conversation, I asked my guys. like why this story about an imminent Yellowstone supererruption bothers him so much. Like, what is the harm he sees in having a story like this out in the world? I think it causes us to focus on the wrong things. Emphasizing something that is the literally one in a million chance, I find it disappointing because it's like, Yellowstone is stunning, right? iconic landscapes, charismatic megafauna, right?

Bison, elk, bears, wolves, oh my. Boiling water is shooting out of the ground at a lot of places with some regularity. That's amazing. It sells itself, but why turning it into this boogeyman? So I think I find that lazy and kind of, if I'm really going to reach, kind of disrespectful to the landscape and to the place. And I do think it distracts from things that are really consequential. So I asked Mike to tell me what he finds consequential about Yellowstone. What it is like to be there.

Well, this is the amazing thing, right? it varies so much in this small corner of Wyoming, right? You will smell pine forest and not be able to see much in any direction because you're in the middle of a really dense forest. And then you'll walk out into a meadow and there'll be a herd of bison in the meadow or across a really cold mountain river, there's a pack of wolves running by, something like that. And then you pass around the corner and you're hit by the smell of rotten eggs. and a weird plume. And as you approach it, there's a rainbow-colored spring

that's steaming and right next to it, boiling water is shooting up out of the ground 100 feet in the air. I got to go to Yellowstone. It is a spectacular landscape with amazing number of stories to tell. If you want to hear more about volcanoes and you want to hear more from Mike Poland, please listen to our episode about the quest to build a magma observatory. It is called The View from Inside a Volcano, and we will link to it in the transcript.

This episode was produced by me, Bird Pinkerton. It was edited by Joanna Salataroff and Julia Longoria, Erica Huang, did the mixing and the sound design, Noah Massenfeld wrote the music, Melissa Hirsch checked our facts, Jorge Just, Meredith Hodnott, Sally Helm, and Amy Padula are the fact that, hedgehogs can swim. Thanks to Thomas Liu for his help in edits on this episode. And I'm always, always, always grateful to Brian Rusnik for co-founding the show with me and Noam.

If you have a long-held belief that you would like us to dig deeper into, or if you have ever had a wild and beautiful time at Yellowstone, please tell us about it. We are at Unexplanable at box.com, and we are always open to your ideas. if you'd like to support this show and the journalism that Vox does, we would love it if you would become a Vox member. It's very easy to do.

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If you wanted to leave us a nice review on your podcast platform, we would appreciate that a lot. Or if you just wanted to tell someone in your life that they might want to listen to the show, that would make a real difference. Genuinely, though, it just makes a big difference that you listen. So thank you. Thanks for listening all the way through the credits. And Unexplanable is part of the Vox Media Podcast Network. We'll be back soon. With another episode about everything we don't yet know.

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