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What If The Yellowstone Super Volcano Erupts Today?
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Mar 31, 2025
Lying underneath Yellowstone National Park is one of the world's few Super Volcanoes. 2.1 million years ago it erupted, spewing ash and debris across most of the continental United States. Today, millions of people visit Yellowstone National Park every year to see beautiful scenery, majestic animals, and awe-inspiring geysers. So what if the Yellowstone Super Volcano erupts today?
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Volcanoes are some of the most awe-inspiring natural phenomenons that Earth creates
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Every once in a while, one rips open, spewing ash, rocks, and lava into the atmosphere
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But while volcanoes are fun to watch from afar, they can also be very destructive
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None more so than the legendary supervolcano that lies underneath Yellowstone National Park
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So what if the Yellowstone supervolcano erupts today? Hello and welcome to What If Geography, where we try and answer the great geographic what-if
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questions of the world. I'm your host Jeff Gibson, and today we're going to talk about
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the Super Volcano, specifically the one underneath the Yellowstone National Park. And while it's not likely to erupt anytime soon, eventually it will need to let off a little steam
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and when it does, it could be a big mess. But before we get into today's episode
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this is just a reminder to follow the What If Geography podcast if you are interested in deeper
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dives on my subjects. The podcast now has its own channel, and you can find it right here on YouTube
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Spotify, Apple Podcasts, or wherever you get your podcasts. A supervolcano is exactly what it sounds like. A volcano that is many times larger than a
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traditional volcano. More specifically, it is a volcano that has a volcanic explosivity index of
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8, which is the highest ranking possible. A volcano with an explosivity index of 4 or less
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emits less than 1 cubic kilometer of magma. From there, it ramps up. At an index of 5
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a volcano will emit more than 1 cubic kilometer of magma. A 6 will emit more than 10 cubic kilometers
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A 7 more than 100 cubic kilometers. And an 8 will emit more than 1,000 cubic kilometers of magma
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as well as an incredible amount of ash into the atmosphere. To put this in perspective
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The Mount St. Helens eruption in 1980 and the Icelandic volcano eruption in 2010
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were both rated at an index of four. That same Icelandic volcano
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despite being relatively low on the index, wreaked havoc on the world
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and managed to disrupt basically all air travel from North America to Europe
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Both of these volcanoes cause enough havoc to be worthy for the history books
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but neither come close to what a supervolcano would do, let alone the Yellowstone supervolcano
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The Yellowstone supervolcano will be truly massive whenever it does have a full eruption
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When Yellowstone last erupted about 2 million years ago it managed to spew 2 cubic kilometers of magma from within the Earth and enough ash to cover most of the continental United States Mount St Helens by contrast managed a relatively small 0 cubic kilometers of magma
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The Yellowstone eruption was approximately 10,000 times larger than the Mount St. Helens eruption
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But while the Yellowstone supervolcano is large, it isn't the only supervolcano in the world
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Three others exist within the western half of the United States. Six are nestled within the Andes Mountains on the border of Chile, Argentina, and Bolivia
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Another on the Indonesian island of Sumatra, and the final within New Zealand, just south of Auckland
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All told, if all of these supervolcanoes exploded at the same time, life on the planet would be in very dire straits
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The largest of these, the supervolcano in Indonesia, last erupted about 75,000 years ago and let loose approximately 13,000 cubic kilometers of magma
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It's worth noting that the Indonesian eruption caused a 10-year global winter event
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and is theorized to have nearly wiped out the budding human population at the time
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Today, the area around the Yellowstone Supervolcano is relatively crowded, and its impact would be felt far and wide if it ever erupted
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In addition to the many cities and towns in the general area, humans have grown to more than 8 billion people since the last eruption
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But before we get into the impacts of a supervolcano eruption, if you're enjoying this video, now would be a great time to subscribe
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More fun what-if geography videos are just a single click away. Before we dive into what an actual supervolcano eruption would do
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it's probably important to clear up some misconceptions around the event. Over the last couple decades, the idea of the Yellowstone supervolcano erupting
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has been mythologized and aggrandized. So let's clear up some stuff first
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A Yellowstone supervolcano eruption would likely not cause an Armageddon-level event. According to the U.S. Geological Survey
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the next time the region erupts, it's most likely going to be a relatively small lava flow event
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that releases the volcanic pressure without the theatrics of a volcanic explosion
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There's always the possibility of a supereruption, which would have global implications
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but that seems to be an incredibly unlikely scenario. Additionally, Yellowstone is not overdue for a supereruption
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While there are many statistics out there trying to show that the continent is overdue
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they are based on only two variables. One super eruption 2.1 million years ago
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and another 640,000 years ago. No matter how you slice it trying to derive a pattern from two events is mathematically impossible We simply don have enough information And again if an eruption does happen
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it would likely be something much more benign. Finally, the region as a whole is not giving any
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hints that a super eruption is imminent. There is no evidence that the magma chamber underneath
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Yellowstone is growing. Yellowstone is not rapidly rising as some like to think
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according to the USGS monitoring. And the earthquakes that have occurred over the last
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few years have not indicated that they're anything more than just that. Simple earthquakes in an
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otherwise geologically complicated area. All this is to say, we don't actually have to worry about a
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super eruption happening within Yellowstone, but it is fun to think about
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If a super eruption did occur, it would be a pivotal moment for the human race
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But luckily, there would probably be plenty of obvious signs leading up to that moment
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For one, there would likely be weeks to months of very intense seismic activity across the entire region
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as the volcano will need to break down the rocks above the magma before it could actually explode
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But after that, the fireworks would really begin. But it still won't be that catastrophic
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At least not in the way you might be thinking. Magma and lava spewing everywhere
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All told, it's estimated that the area of magma exposure would be contained to around 40 square kilometers
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That's a huge volcanic eruption to be sure. But again, not really impactful enough to cause anyone outside of the immediate area
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to be in any danger of falling into a lava pit. What would be catastrophic, however, would be the ash cloud
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With a super eruption, most areas of the United States would receive at least some ash falling on them
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But the areas around the park would be hit the hardest. It's estimated that the states of Idaho, Montana, Wyoming, Utah, and Colorado
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would be inundated by upwards of 3 feet of ash. This would likely include the major metropolitan areas of Denver, Salt Lake City, and Boise
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and smaller cities such as Billings, Cheyenne, and Missoula. And while ash might not seem like that big of a deal
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that much ash is absolutely capable of killing humans, animals, and plant life
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It's also very likely to crush buildings and vehicles under the weight of it
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Ash is, after all, just small bits of rock and glass. Once you get enough of it together, it becomes quite heavy
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Even a single inch of ash, which is what Minneapolis, Chicago, Kansas City, Phoenix
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Los Angeles and San Francisco can likely expect can clog roadways and plumbing and cause serious respiratory issues for people At the very least air travel would absolutely be halted throughout the entire continent But while the human impacts would be huge it probably the global impact on the climate that would have the biggest
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ramifications. In an odd turn of events, a super eruption would put a temporary halt to global
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warming. But that wouldn't necessarily be a good thing. You see, when a volcano erupts
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it sends sulfur aerosols into the atmosphere, which reflect light and heat back into space
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But while this is only a temporary effect, it would still have a dramatic impact on the planet
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To put this in perspective, when Pinatubo erupted in 1991, the planet cooled by 1 degree Celsius
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for a few years. Even more severe, the Tambora eruption in the early 1800s cooled the planet
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down enough that it damaged crops globally in what is now considered to be the year without summer
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In fact, that eruption is theorized to have led to many famines around the world
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as well as a general discontentment among populations in various countries. In Germany, for example, there were riots and protests due to the lack of food
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A super eruption would wreak havoc on international agriculture. More specifically, US agriculture would basically collapse for at least a few years
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This would undoubtedly cause food shortages within the United States, Canada, and Mexico
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but the world would also suffer. The United States specifically exports a lot of food to other countries
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If agriculture were to collapse in the United States, the world would need to figure out where a large portion of its food was going to come from
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and with now over 8 billion people to feed, I'm not sure if that would even be possible
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But to add further context, earlier in 2022, Russia invaded Ukraine, which is a major wheat exporting country
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Given that so much of the world relied on Ukraine for food, it's no surprise that a global food shortage hit soon after
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If a war within a single country can cause this much damage, a super eruption in one of the largest agriculture producing countries in the world
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would be absolutely devastating. While the Yellowstone supervolcano could potentially erupt, the likelihood of that actually happening is incredibly small
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Which is a very good thing. Our society at large is not prepared to handle a major earthquake in California or the Pacific Northwest
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let alone such a cataclysmic event. Today, the Yellowstone National Park maintains as a beautiful place to visit and explore
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And let's hope it stays that way. I hope you enjoyed today's episode on the Yellowstone Supervolcano
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If you did, please subscribe to my channel. And if you wanna watch more of my videos
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you can do so here. Thanks for watching, see you next time
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