# Yellowstone Supervolcano Timing Question
**URL:** https://boards.straightdope.com/t/yellowstone-supervolcano-timing-question/716864
**Category:** Factual Questions
**Created:** [April 5, 2015, 8:56am UTC](https://boards.straightdope.com/t/yellowstone-supervolcano-timing-question/716864 "2015-04-05T08:56:26Z")
**Posts on this page:** 20
**Page:** 2
### Author:  [@the\_diego](https://boards.straightdope.com/u/the_diego)
#### Post date: [April 6, 2015, 12:53am UTC](https://boards.straightdope.com/t/yellowstone-supervolcano-timing-question/716864/21 "2015-04-06T00:53:09Z")
Actually, ash fall in a big eruption is not a near term thing. Pinatubo ash thrown high in the atmosphere in 1991 stayed aloft long enough to affect 1992 harvests around the world.
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### Author:  [@LSLGuy](https://boards.straightdope.com/u/LSLGuy)
#### Post date: [April 6, 2015, 1:54am UTC](https://boards.straightdope.com/t/yellowstone-supervolcano-timing-question/716864/22 "2015-04-06T01:54:11Z")
Volcanic soil is \*eventually \*fertile. A couple decades after the lava cools and enough weathering has happened to let the first few generations of crude grasses add some biomass to the “soil”.
Areas of heavy ash fall would look like the moon for years, regardless of how much sun or rainfall they might receive.
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### Author:  [@jezzaOZ](https://boards.straightdope.com/u/jezzaOZ)
#### Post date: [April 6, 2015, 2:30am UTC](https://boards.straightdope.com/t/yellowstone-supervolcano-timing-question/716864/23 "2015-04-06T02:30:11Z")
I remember reading somewhere, but can’t find it again, that some eruptions are completely unpredictable because they occur when a huge blob of magma breaks free and accelerates upward reaching supersonic speeds
It breaks through without minimal to zero warning
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### Author:  [@MrDibble](https://boards.straightdope.com/u/MrDibble)
#### Post date: [April 6, 2015, 8:35am UTC](https://boards.straightdope.com/t/yellowstone-supervolcano-timing-question/716864/24 "2015-04-06T08:35:57Z")
> [@jezzaOZ](#):
>
> I remember reading somewhere, but can’t find it again, that some eruptions are completely unpredictable because they occur when a huge blob of magma breaks free and accelerates upward reaching supersonic speeds
>
> It breaks through without minimal to zero warning
Those arekimberlite or lamproite eruptions. Yellowstone isn’t like that, the magma chamber isn’t that deep and it’s not ultramafic.
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### Author:  [@Broomstick](https://boards.straightdope.com/u/Broomstick)
#### Post date: [April 6, 2015, 1:50pm UTC](https://boards.straightdope.com/t/yellowstone-supervolcano-timing-question/716864/25 "2015-04-06T13:50:04Z")
> [@Lumpy](#):
>
> It wouldn’t be world-destroying, based on the three known eruptions in the past. The western half of the United States would be in bad shape, and maybe there would be a few years of global cooling that played havoc with world agriculture.
Havoc with world agriculture? It would take out one of the most fertile and productive regions of farmland for _decades_ and likely generate several “years without a summer”, screwing growing seasons for the rest of the planet. The only people not suffering horribly will be the nutters who stocked up on canned food for Y2K or a zombie apocalypse or something. Lots of people will starve.
> [@](#):
>
> Once you were down to the last few months/ year, when smoke and ash were spewing into the air, people would start migrating out of the area.
Er… you’re assuming we’d get that sort of warning. Since we’ve never seen a supervolcano eruption we haven’t a clue what a warning would look like, but we do know that smaller volcanoes don’t always given the same sorts of warnings.
> [@](#):
>
> Maybe there would first be a federally ordered evacuation of the immediate surrounding area, with the evacuation zone expanding as the estimates became sooner and/or worse.
Define “immediate surrounding area”. I’ve read estimates that _90% of people within 1,000 kilometers of the eruption will die_. Granted, that’s a worse case scenario and an actual event may be only half that or whatever… but we can’t fully evacuate the city of New Orleans even if we know a category 5 hurricane that will smash levees and cause massive flooding is on the way with an estimate of landfall down to the quarter hour, no way in hell can we evacuate more than a tiny fraction of central North America
> [@](#):
>
> The biggest immediate problem would be ashfall. It’s thought that previous eruptions caused massive wildlife death due to the effects of breathing ash. Filtering masks and systems might make it feasible to shelter in place in the lesser affected regions.
Er… sure, if you can also find a way to get sufficient food, water, fuel, replacement masks, medical care, etc. into the affected zone, which will be _huge_. The big historical ash falls from Yellowstone extended from Canada down to Texas, and from California to Illinois. The ash will be measured in feet, not inches, and will be a problem for an extended period of time. You’ll either need to wear a mask 24/7 or install airlocks on your living quarters because that dust will get everywhere.
And, oh yeah, that dust renders aircraft useless and will muck up road vehicles, too, unless you equip them will some sort of very efficient filter, which will need on-going maintenance.
> [@](#):
>
> Long term, it becomes a political and economic question of the US dealing with a cataclysmic blow that sharply reduces its economic output.
Also sharply reduces population and for a few years likely make the US unable to feed itself. Lots of people dead, lots of people trying to flee in Canada and Mexico. It’s questionable if the US would survive a really big Yellowstone eruption.
> [@Quartz](#):
>
> Surely ashfall will be a very short-term thing, ending with the first rain? In the longer term, it should be a huge boon to the US as volcanic soil is super-fertile.
Um… no.
First of all, as I note, the ashfall will be enormous in extent, covering half the continental US. It will be measured in feet in most place, not inches. The first rain, and subsequent one, will tend to turn it into a cement-like substance. You’ll have a lot of building collapses, because no one builds a roof with withstand that sort of load.
Volcanic soil is “super-fertile” _after weathering_, which will take decades. Examine Hawaii, which has life adapted to colonizing post-eruption zones. While life shows up pretty soon it’s not plant and animal life useful to humans. It will take _decades_, at the soonest, for agriculture to be possible again in the affect areas, and that’s _after_ the eruption stops. How long does a super-eruption continue? We have no clue. Two weeks? Two months? Two years? Two decades?
We’ll lose the entire Midwest corn and wheat belts. We might also lose the California Central Valley if the wind is blowing the wrong way on Eruption Day. Agriculture may or may not be possible on any level in the Eastern half of the US for quite some time, and will be marginal for awhile after that due to ash and climate changes. Yeah, a few decades after Yellowstone goes to sleep people can re-colonize the central part of North America.
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### Author:  [@Anne\_Neville](https://boards.straightdope.com/u/Anne_Neville)
#### Post date: [April 6, 2015, 2:06pm UTC](https://boards.straightdope.com/t/yellowstone-supervolcano-timing-question/716864/26 "2015-04-06T14:06:00Z")
Nobody really knows for sure, because there have not been any literate (let alone scientifically trained) observers of a supervolcano eruption and what led up to it. Even regular volcanoes, which have been extensively studied by modern science, can still manage to surprise geologists.
If you did know that Yellowstone was going to blow, and on a specific date (we probably wouldn’t know to that level of specificity), then what? Evacuate the Midwest and Mountain West? It’s hard enough to evacuate one city when you know a hurricane is coming. It gets worse if you have a few false alarms before the actual eruption. If you wait until after the eruption starts to start the evacuation, you’ve got the problem of [volcanic ash doing nasty things to car and plane engines](http://en.wikipedia.org/wiki/British_Airways_Flight_9).
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### Author:  [@Quartz](https://boards.straightdope.com/u/Quartz)
#### Post date: [April 6, 2015, 3:20pm UTC](https://boards.straightdope.com/t/yellowstone-supervolcano-timing-question/716864/27 "2015-04-06T15:20:49Z")
> [@Broomstick](#):
>
> Um… no.
>
> First of all, as I note, the ashfall will be enormous in extent, covering half the continental US. It will be measured in feet in most place, not inches. The first rain, and subsequent one, will tend to turn it into a cement-like substance. You’ll have a lot of building collapses, because no one builds a roof with withstand that sort of load.
I would hope that people would brush it off before the rains come. Even if they don’t collapsed buildings can be easily restored - look at the post WW2 pre-fab buildings in the U.K.
> [@](#):
>
> Volcanic soil is “super-fertile” _after weathering_, which will take decades.
We’re talking about ash, not lava. Ash requires no weathering. It could be ploughed straight in, which would also prevent it being blown away.
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### Author:  [@Anne\_Neville](https://boards.straightdope.com/u/Anne_Neville)
#### Post date: [April 6, 2015, 3:43pm UTC](https://boards.straightdope.com/t/yellowstone-supervolcano-timing-question/716864/28 "2015-04-06T15:43:46Z")
> [@Quartz](#):
>
> I would hope that people would brush it off before the rains come. Even if they don’t collapsed buildings can be easily restored - look at the post WW2 pre-fab buildings in the U.K.
Couple of problems with this:
[Inhaling volcanic ash is quite bad for your lungs.](http://en.wikipedia.org/wiki/Silicosis) You’d need a way of keeping people from inhaling the ash while cleaning it off their roofs. Spraying it with water, which is a method used to control silica dust in workplaces where it is a problem, isn’t going to work here. It might cause the roofs to collapse. You’d need to provide air filters for people to wear. It’s probably not such a good thing to get in your eyes, either, so people will need eye protection.
That runs into another problem, which is also going to be a problem for rebuilding. Car, truck, and plane engines are also affected badly by volcanic ash. That’s a problem if you need to get a lot of air filters distributed. It’s also a problem for construction equipment needed to rebuild collapsed buildings.
You’re also assuming that most homeowners are capable of safely getting up on their roofs and sweeping off volcanic ash. We own a home (in Pittsburgh), and we don’t have a ladder that would let us get up on the roof. We hire a roofing and gutter cleaning service for when it is required. We’re not handicapped or elderly, just afraid of heights. I imagine we could get up on our roof if we had the proper ladder and really had to. There are other homeowners who are less capable of getting up on a roof than we are. Also, in this case, you wouldn’t just need to get up on the roof- you’d need to do it while wearing eye protection and some kind of respiratory filter. In the case of the airliner that went through an ash cloud, the ash essentially sandblasted the aircraft’s windshield. Something similar might happen to any kind of eye protection people are wearing (though probably less so, since they won’t be moving at airplane speeds), which is going to lead to reduced visibility. Reduced visibility and climbing around on roofs doesn’t seem like such a good combination, especially for people who don’t normally climb around on roofs. You’re going to have people getting injured. They will have to rely on an already stressed medical care system (because you will have a lot of other people who have inhaled ash and need medical treatment), as well as problems transporting people to hospitals or urgent care clinics.
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### Author:  [@Broomstick](https://boards.straightdope.com/u/Broomstick)
#### Post date: [April 6, 2015, 3:49pm UTC](https://boards.straightdope.com/t/yellowstone-supervolcano-timing-question/716864/29 "2015-04-06T15:49:48Z")
> [@Quartz](#):
>
> I would hope that people would brush it off before the rains come. Even if they don’t collapsed buildings can be easily restored - look at the post WW2 pre-fab buildings in the U.K.
I think there’s a lack of understanding here - volcanic ash isn’t snow, and even though snow is lighter than ash it can still build up to the point of collapsing roofs. Even in areas where volcanoes are a local hazard and the locals are familiar with ashfall there are _still_ problems with roof collapses.
You’d be talking about an ashfall of record proportions across _half a continent_. Even if nothing else was undertaken the logistics of sweeping off all those roofs would be impossible. But it wouldn’t be the sole occupation of residents, everyone would be trying to get the hell out of Dodge.
On top of that, volcanic ash is basically ground glass, but sharper. It’s teeny little glass fragments. That shit is abrasive, damaging, and breathing enough of it in will kill you. So, you’ll have people fleeing rather than helping out with roof rescue, and those who are stupid enough to stay and sweep roofs will either need respirators, which will make the job even harder and more uncomfortable, or will be quickly incapacitated by, essentially, inhaling ground glass particles.
These by the way, are the reasons that even with smaller volcanic eruptions the usual practice is to _abandon_ the buildings, letting whatever happens happen, and only coming back later when the eruption is over and the area is much safer. Even then, inhaling too much volcanic dust that is loose and kicked up by wind and work is still quite hazardous.
Yellowstone erupting would be several orders of magnitude worse than any historical volcanic eruption, including Krakatoa and the Toba eruption, the latter of which is “historical” only if you stretch the term to “within the lifetime of our species”.
> [@](#):
>
> We’re talking about ash, not lava. Ash requires no weathering. It could be ploughed straight in, which would also prevent it being blown away.
You’re talking about several feet of what is essentially sterilized ground glass particles. There is no organic matter in it to start. This isn’t a sprinkling of mineral goodness on top of healthy soil, it’s a _couple feet_ of powdered glass. It has to be re-colonized by specialist plants in order to become suitable for agriculture again. All the normal mechanisms of ash turnover, such as ground-dwelling animals burrowing and digging that churns the soil, will be non-existent because groundhogs and rodents of various sorts are NOT going to be able to dig through that much ash before suffocating even if overlying dirt shields them from superheated air/rock/ash and/or poisonous gasses.
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### Author:  [@MrDibble](https://boards.straightdope.com/u/MrDibble)
#### Post date: [April 6, 2015, 3:52pm UTC](https://boards.straightdope.com/t/yellowstone-supervolcano-timing-question/716864/30 "2015-04-06T15:52:36Z")
> [@Quartz](#):
>
> We’re talking about ash, not lava. Ash requires no weathering.
What, exactly, do you think volcanic ash _is_? It’s little shards of basalt glass, which _does_ require weathering before it becomes the clays that make up fertile soil.
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### Author:  [@Boyo\_Jim](https://boards.straightdope.com/u/Boyo_Jim)
#### Post date: [April 6, 2015, 3:58pm UTC](https://boards.straightdope.com/t/yellowstone-supervolcano-timing-question/716864/31 "2015-04-06T15:58:25Z")
> [@Shakes](#):
>
> I have no idea. I do know they had plenty of warning when Mt St. Helens errupted.
>
> I was only 10yo when it happened, but IIRC, they knew weeks ahead of time.
No, this isn’t true at all. They knew the volcano was active and shaking, but they had no idea it was going to erupt so spectacularly until it happened.
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### Author:  [@Anne\_Neville](https://boards.straightdope.com/u/Anne_Neville)
#### Post date: [April 6, 2015, 4:26pm UTC](https://boards.straightdope.com/t/yellowstone-supervolcano-timing-question/716864/32 "2015-04-06T16:26:21Z")
> [@Broomstick](#):
>
> This isn’t a sprinkling of mineral goodness on top of healthy soil
There are lots of things that, when added to soil _in moderate quantities_, are good for things growing in the soil, but it’s a problem when you have too much of it. You can get [fertilizer burn](http://en.wikipedia.org/wiki/Fertilizer_burn) from adding too much fertilizer with nitrogen salts to soil. Just because some volcanic ash is good for growing things, doesn’t mean that several feet of it dumped on all at once is.
They had problems in Boston this winter of where to put all the snow they were plowing out of streets, driveways, etc. That’s going to be orders of magnitude worse with volcanic ash. Snow isn’t as hazardous to plow or be around as volcanic ash. Snow _melts_, volcanic ash doesn’t (at least not at any temperatures you’re likely to find on Earth). There are pollution problems with dumping snow into rivers and such (as they had to do with snow in Boston this winter), but dumping volcanic ash is going to be much, much worse.
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### Author:  [@silenus](https://boards.straightdope.com/u/silenus)
#### Post date: [April 6, 2015, 4:35pm UTC](https://boards.straightdope.com/t/yellowstone-supervolcano-timing-question/716864/33 "2015-04-06T16:35:11Z")
Just as a side note: Harry Turtledove has an on-going [series of novels](http://www.amazon.com/Supervolcano-Eruption-Harry-Turtledove-ebook/dp/B005ERIKF6/ref=sr_1_3?ie=UTF8&qid=1428337973&sr=8-3&keywords=supervolcano) about just this thing happening. Some interesting story developments happen because of all the ash.
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### Author:  [@Northern\_Piper](https://boards.straightdope.com/u/Northern_Piper)
#### Post date: [April 6, 2015, 4:38pm UTC](https://boards.straightdope.com/t/yellowstone-supervolcano-timing-question/716864/34 "2015-04-06T16:38:45Z")
Here’s a recent article summarising the issues:
[If the Yellowstone Supervolcano ever blew its top, this new study shows us what to expect](http://www.theweathernetwork.com/news/articles/if-the-yellowstone-supervolcano-ever-blew-its-top-this-new-study-shows-us-what-to-expect/35720/)
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### Author:  [@Anne\_Neville](https://boards.straightdope.com/u/Anne_Neville)
#### Post date: [April 6, 2015, 4:58pm UTC](https://boards.straightdope.com/t/yellowstone-supervolcano-timing-question/716864/35 "2015-04-06T16:58:16Z")
If you want to plow anything into soil, you need tractors or draft animals. Both of those are going to have trouble operating with volcanic ash blowing around. Animals will have the same problems that people do with breathing in volcanic ash. [We’ve found fossilized animals that died from breathing ash from a previous eruption of Yellowstone](http://museum.unl.edu/research/vertpaleo/ashfall.html), from a site in [northeastern Nebraska](http://en.wikipedia.org/wiki/Ashfall_Fossil_Beds). Tractor engines are going to have the same kind of problems that car or plane engines do with volcanic ash.
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### Author:  [@dracoi](https://boards.straightdope.com/u/dracoi)
#### Post date: [April 6, 2015, 4:59pm UTC](https://boards.straightdope.com/t/yellowstone-supervolcano-timing-question/716864/36 "2015-04-06T16:59:15Z")
> [@Quartz](#):
>
> Surely ashfall will be a very short-term thing, ending with the first rain? In the longer term, it should be a huge boon to the US as volcanic soil is super-fertile.
Other people have talked about the heavy localized ash fall that would be one problem.
Another problem, though: the particulates that block sunlight and changes the global climate is above the rain. It’s the ash that gets injected into the stratosphere and can remain there for decades. Pinatubo, for example, reduced average global temperatures by about 1 F for 3 years.
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### Author:  [@Quartz](https://boards.straightdope.com/u/Quartz)
#### Post date: [April 6, 2015, 5:01pm UTC](https://boards.straightdope.com/t/yellowstone-supervolcano-timing-question/716864/37 "2015-04-06T17:01:05Z")
> [@MrDibble](#):
>
> What, exactly, do you think volcanic ash _is_? It’s little shards of basalt glass,
And loads of other stuff - pumice, tephra, etc. But the point is the pieces are very small, which means that unlike solidified lava, there is a high surface area to volume ratio. which means that bacteria and plants can draw sustenance very quickly. You only have to look at how quickly plants colonise other ash-strewn locations without human help to see this. Yes, we’re still talking years, but not decades.
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### Author:  [@md2000](https://boards.straightdope.com/u/md2000)
#### Post date: [April 6, 2015, 5:50pm UTC](https://boards.straightdope.com/t/yellowstone-supervolcano-timing-question/716864/38 "2015-04-06T17:50:48Z")
> [@Northern\_Piper](#):
>
> Here’s a recent article summarising the issues:
>
> [If the Yellowstone Supervolcano ever blew its top, this new study shows us what to expect](http://www.theweathernetwork.com/news/articles/if-the-yellowstone-supervolcano-ever-blew-its-top-this-new-study-shows-us-what-to-expect/35720/)
Thanks; interesting, and not quite as apocalyptic. Calgary, Seattle, Frisco and LA, Albuquerque, Kansas City and Minneapolis, maybe Chicago, would get about half an inch to an inch of ash; not fun, but not what everyone seems to be talking about, the feet of ash that would incapacitate the entire Midwest. I guess the question is what a good rainfall would do with that? you’d have clear areas, gullies and rivers clogged with a cement-like covering, plenty of trees and shrubs poking through to allow the soil below to function, etc. Even the 100mm (4 inch) zone is not that big.
After all, think about it. There may be plenty of fine particulate trapped in the upper atmosphere, but where would several feet of ash burying the Louisiana Purchase come from?
As for warnings, no, they had ample warning something was coming for months for Mt. St. Helens; the only question was exactly when, how big, and “are we sure we are reading this right”? They evacuated people well ahead of time, so only stubborn old coots (coot?) who refused to leave ended up doing the Pompeii cavity thing.
IIRC one of the best warnings was the growing bulging dome indicating pressure buildup from below.
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### Author:  [@Lumpy](https://boards.straightdope.com/u/Lumpy)
#### Post date: [April 6, 2015, 6:06pm UTC](https://boards.straightdope.com/t/yellowstone-supervolcano-timing-question/716864/39 "2015-04-06T18:06:26Z")
> [@Northern\_Piper](#):
>
> Here’s a recent article summarising the issues:
>
> [If the Yellowstone Supervolcano ever blew its top, this new study shows us what to expect](http://www.theweathernetwork.com/news/articles/if-the-yellowstone-supervolcano-ever-blew-its-top-this-new-study-shows-us-what-to-expect/35720/)
I added a comment rewording their picture caption:
> [@](#):
>
> "This simulated view of a Yellowstone eruption gives an idea of what the [first] LAST moments of [the event]THEIR LIFE would be like to anyone in the park that day (Credit: Discovery/YouTube)
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### Author:  [@MrDibble](https://boards.straightdope.com/u/MrDibble)
#### Post date: [April 6, 2015, 9:48pm UTC](https://boards.straightdope.com/t/yellowstone-supervolcano-timing-question/716864/40 "2015-04-06T21:48:42Z")
> [@Quartz](#):
>
> And loads of other stuff - pumice, tephra, etc.
Pumice is still glass, with bubbles in it.
And ash can’t _contain_ [tephra](http://en.wikipedia.org/wiki/Tephra#Classification), since ash is a size _subclass_ of tephra, which just means ejecta regardless of size. And anything further than say, [a couple hundred kilometers away](http://volcanoes.usgs.gov/ash/properties.html), is just going to be ash.
Ash can contain other minerals as well, but the fine stuff, any distance away, is mostly going to be glass because of density.
> [@](#):
>
> But the point is the pieces are very small, which means that unlike solidified lava, there is a high surface area to volume ratio.
Unless the ash fuses as a [tuff](http://en.wikipedia.org/wiki/Tuff).
> [@](#):
>
> which means that bacteria and plants can draw sustenance very quickly.
Plants and most bacteria are not really capable of drawing their nourishment from the silicate minerals that make up basalt (hence ash). They need it to be broken down by chemical weathering first.
> [@](#):
>
> You only have to look at how quickly plants colonise other ash-strewn locations without human help to see this. Yes, we’re still talking years, but not decades.
The USGS [thinks differently](http://volcanoes.usgs.gov/ash/agric/#rehab). For anything from 4"-1’:
> [@](#):
>
> Rehabilitation extremely difficult and likely to take generations.
> Soil sterilized below ash.
> Ash too deep to be incorporated using conventional cultivation techniques, including ploughing, discing or rotatilling.
> Restoration dependent on removal of the ash layer or a much longer time frame of re-colonization of the ash layer.
and worse if more than a foot.
Some particular species may colonize on your “years” timeframe. But farming? Forget about it.
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