one of the world's largest volcanoes

is gearing up to explode.

It's known as the Yellowstone Volcano,

and it's not just any regular volcano.

Nope.

It's a supervolcano!

If Yellowstone decided to erupt,

the results would be devastating.

But just how bad would they be?

Located in Wyoming, United States,

Yellowstone has erupted three times

in the past 2 million years.

This has led some people to wonder whether

we should be worried about another Yellowstone eruption

in the near future.

And by "near future,"

we mean probably in another

couple hundred thousand years.

But instead of waiting so long,

why don't we find out,

what would happen

if the eruption took place tomorrow?

If you live in North America,

there would be virtually nothing you could do to prepare.

Now that this supervolcano has exploded...

Well first,

what makes Yellowstone a supervolcano anyway?

Apart from it being larger in size,

a supervolcano also produces

a much more massive explosion.

Most of the time,

when we think of a volcanic eruption,

we think of the hot,

molten lava spewing down,

covering the surrounding area.

While that would happen at Yellowstone,

and it is something you'd need to worry about,

it wouldn't be the only thing.

In fact, the lava pouring out of the volcano

might be the least of your worries.

Surprisingly, there wouldn't be much of it,

at least not as much as you'd expect

from a supervolcano.

That's because before lava leaves a volcano,

it's first known as magma.

But in this case,

a lot of Yellowstone's magma

won't be able to become lava.

That's because it will be shot up into the sky,

becoming airborne ash particles.

And it won't just be any type of ash.

These will be tiny, scorching particles of jagged rock.

This would affect nearly the entire United States

and Canada.

Tens of millions of people

within 1,000 km (621 mi) of the eruption would die.

If you breathed the ash,

which would be inevitable in a scenario like this,

it would form a cement-like mixture in your lungs,

causing you to suffocate.

Buildings would collapse,

as just 30 cm (12 in) of ash

is enough to cave roofs in.

And you'd still be in trouble

even if you were outside that 1,000 km (621 mi) range.

Experts say that

even the east coast of the United States

would be covered in 1 cm (0.4 in) of ash,

which would still be incredibly dangerous

to our human lungs.

Even parts of Europe would see some ash,

maybe a light dusting.

And that wouldn't be the only effect they'd experience.

Apart from the deadly ash everywhere,

the entire world would experience a temperature drop.

The ash lingering in the air

would block out the Sun,

resulting in significant weather changes.

The global temperature would drop by 10 degrees,

an effect which could last as long as a decade.

The ash would also affect crops,

water supply, and

virtually everything else in the western part of the world.

So although you'd probably survive

the initial explosion,

you'd eventually suffer the consequences of the ash,

whether that means dying relatively quickly,

or living long enough to experience

a colder, harsher world.

Luckily, you can take a deep breath of

ashless oxygen, knowing that something like this will

probably never happen,

at least not in our lifetime.

An eruption like this at Yellowstone

would be known as a supervolcanic eruption.

A more likely explosion at Yellowstone

would be a hydrothermal eruption.

This mainly involves a lot of steam,

and some rocks hurling through the air.

Although something like this would be bad,

it wouldn't be nearly as scary as

what we're getting here.

And an even more likely eruption at Yellowstone

would be a relatively simple lava flow.

In fact, since the last major explosion

600,000 years ago,

we've had nearly 50 of these eruptions

and 0 casualties.

We know one way to almost certainly get killed by lava

and it involves dropping your trash into it.

But that's a story for another WHAT IF.