- Did you know that wildfires can create their own weather?
- Did you know that wildfires can create their own weather?

Did you know that they can create their own tornadoes?
Did you know that they can create their own tornadoes?

Can you even imagine something scarier than a firenado.
Can you even imagine something scarier than a firenado.

As the climate warms and more acres burn each year,
As the climate warms and more acres burn each year,

it's clear that the risk from wildfires is real and growing.
it's clear that the risk from wildfires is real and growing.

Warmer, drier weather changes fire,
Warmer, drier weather changes fire,

but fire also changes weather.
but fire also changes weather.

And fire tornadoes are one of the most obvious examples.
And fire tornadoes are one of the most obvious examples.

In the last few years,
In the last few years,

there've been more sightings and even video
there've been more sightings and even video

of these than ever before,
of these than ever before,

making experts wonder are these rare events
making experts wonder are these rare events

becoming more common?
becoming more common?

The most extreme was in Redding, California,
The most extreme was in Redding, California,

where there was the equivalent to an EF3 tornado
where there was the equivalent to an EF3 tornado

during a major wildfire.
during a major wildfire.

The Carr Fire that spawned that fire tornado
The Carr Fire that spawned that fire tornado

destroyed over 1,600 structures and claimed eight lives.
destroyed over 1,600 structures and claimed eight lives.

So we're visiting a lab where researchers create
So we're visiting a lab where researchers create

and study fire tornadoes to figure out what's going on.
and study fire tornadoes to figure out what's going on.

Definitely watch to the end of this one,
Definitely watch to the end of this one,

because it's not all doom and gloom.
because it's not all doom and gloom.

We have some rare, but important good news
We have some rare, but important good news

about wildfire and climate.
about wildfire and climate.

But first, let's see a fire tornado.
But first, let's see a fire tornado.

(intense music)
(intense music)

- Hey Maiya. - How are you?
- Hey Maiya. - How are you?

Yes, Jason right?
Yes, Jason right?

- That's right.
- That's right.

- I am still trying to wrap my mind around fire tornadoes.
- I am still trying to wrap my mind around fire tornadoes.

- It's kind of like "Sharknado" or something like that.
- It's kind of like "Sharknado" or something like that.

It's pretty crazy and actually pretty scary, the real thing.
It's pretty crazy and actually pretty scary, the real thing.

So it really is the two words combined.
So it really is the two words combined.

It's basically a tornado.
It's basically a tornado.

I mean, at the worst case,
I mean, at the worst case,

it's a full-size tornado that occurs in a fire area.
it's a full-size tornado that occurs in a fire area.

And so it's actually caused by the fire.
And so it's actually caused by the fire.

- [Maiya] So are we gonna see that today here?
- [Maiya] So are we gonna see that today here?

- Absolutely.
- Absolutely.

- [Maiya] Jason is able to observe the dynamics
- [Maiya] Jason is able to observe the dynamics

and the behavior of a fire whirl
and the behavior of a fire whirl

in the controlled environment of the lab.
in the controlled environment of the lab.

- [Jason] You really need two main ingredients.
- [Jason] You really need two main ingredients.

You need, what we call vorticity,
You need, what we call vorticity,

which is just rotating air.
which is just rotating air.

And then you need a way to stretch that rotating air.
And then you need a way to stretch that rotating air.

(suspenseful music)
(suspenseful music)

You can see it's starting to spin up there.
You can see it's starting to spin up there.

- You don't have to do anything else?
- You don't have to do anything else?

Wow, whoa.
Wow, whoa.

- It kind of self drives itself.
- It kind of self drives itself.

- Oh my gosh.
- Oh my gosh.

As we learned in season one of "Weathered,"
As we learned in season one of "Weathered,"

a normal tornado gets its rotation when there is wind shear
a normal tornado gets its rotation when there is wind shear

with two wind currents flowing from different directions,
with two wind currents flowing from different directions,

then a supercell thunderstorm pushes the rotating air up,
then a supercell thunderstorm pushes the rotating air up,

stretching the storm and increasing the speed of rotation.
stretching the storm and increasing the speed of rotation.

(ominous music)
(ominous music)

- [Jason] And so the stretching mechanism in a fire tornado
- [Jason] And so the stretching mechanism in a fire tornado

is actually the fire itself.
is actually the fire itself.

So the buoyant accelerating air
So the buoyant accelerating air

that the fire is causing above the fire,
that the fire is causing above the fire,

that acceleration is what causes that stretching
that acceleration is what causes that stretching

and that stretching, just like stretching a piece
and that stretching, just like stretching a piece

of Play-Doh, shrinks
of Play-Doh, shrinks

the diameter of that mass of air.
the diameter of that mass of air.

And that shrinking diameter causes it to spin faster.
And that shrinking diameter causes it to spin faster.

- That's called the conservation of angular momentum.
- That's called the conservation of angular momentum.

When an ice skater moves their arms inward,
When an ice skater moves their arms inward,

the mass is moving closer to the center,
the mass is moving closer to the center,

and allows the skater to spin faster.
and allows the skater to spin faster.

The fire whirl does the same thing,
The fire whirl does the same thing,

as the buoyant accelerating air from the fire
as the buoyant accelerating air from the fire

pulls the world upward stretching and tightening the spiral.
pulls the world upward stretching and tightening the spiral.

To understand where the initial rotation comes from,
To understand where the initial rotation comes from,

Jason set up an experiment to show me how this might happen
Jason set up an experiment to show me how this might happen

in the real world.
in the real world.

- We have some fire resistant pads that we're placing.
- We have some fire resistant pads that we're placing.

Then we're gonna roll on some alcohol,
Then we're gonna roll on some alcohol,

and then we're gonna light each of these.
and then we're gonna light each of these.

And so what this is really representing is,
And so what this is really representing is,

is a way that a fire whirl can form out in the real world
is a way that a fire whirl can form out in the real world

where you have several fires that are interacting.
where you have several fires that are interacting.

Each fire is causing this hot buoyant gas
Each fire is causing this hot buoyant gas

to form above it when it burns.
to form above it when it burns.

That gas wants to go up.
That gas wants to go up.

This fire in the middle,
This fire in the middle,

the only place that air can come in to replace it
the only place that air can come in to replace it

is through these gaps.
is through these gaps.

So there's a gap here, a gap there, and a gap over there,
So there's a gap here, a gap there, and a gap over there,

and they cause this rotating air.
and they cause this rotating air.

And in the end, it causes rotation,
And in the end, it causes rotation,

which spins up into a fire whirl in the middle.
which spins up into a fire whirl in the middle.

And so this could happen out in the real world in the case
And so this could happen out in the real world in the case

where you have some embers that loft into the air
where you have some embers that loft into the air

and start what we call spot fires
and start what we call spot fires

or a bunch of different fires.
or a bunch of different fires.

And if they happen to form
And if they happen to form

in certain configurations randomly,
in certain configurations randomly,

it can actually spin up to a fire whirl.
it can actually spin up to a fire whirl.

- It's easy to imagine how this could become more common
- It's easy to imagine how this could become more common

as more acres burn in wildfires each year.
as more acres burn in wildfires each year.

There are just more opportunities for topography
There are just more opportunities for topography

or the arrangement of spot fires
or the arrangement of spot fires

to create a similar formation
to create a similar formation

and add the rotation needed for a tornado.
and add the rotation needed for a tornado.

(torch blaring)
(torch blaring)

Oh, there it is.
Oh, there it is.

There's a fire tornado.
There's a fire tornado.

That is crazy.
That is crazy.

While smaller fire whirls are more common,
While smaller fire whirls are more common,

there's still a lot that scientists don't know
there's still a lot that scientists don't know

about true fire tornadoes,
about true fire tornadoes,

including whether or not they're happening more frequently.
including whether or not they're happening more frequently.

This makes Jason's research all the more critical.
This makes Jason's research all the more critical.

What we do know is that the spinning motion
What we do know is that the spinning motion

delivers oxygen very efficiently,
delivers oxygen very efficiently,

allowing fuel to burn dangerously fast.
allowing fuel to burn dangerously fast.

And that's something that the fire lab has begun to include
And that's something that the fire lab has begun to include

in firefighter trainings,
in firefighter trainings,

after the tragic events of the Carr Fire.
after the tragic events of the Carr Fire.

So we know that fires can create their own weather,
So we know that fires can create their own weather,

but fires are also driven by weather, right?
but fires are also driven by weather, right?

- Yeah, yeah.
- Yeah, yeah.

It's kind of a two way thing.
It's kind of a two way thing.

- How important is weather in determining the severity
- How important is weather in determining the severity

of the fire?
of the fire?

- Weather's huge.
- Weather's huge.

So we're developing some new fire behavior models,
So we're developing some new fire behavior models,

computer models, that predict how a fire spreads.
computer models, that predict how a fire spreads.

We use experiments in this lab to generate a lot
We use experiments in this lab to generate a lot

of that information that goes into that model.
of that information that goes into that model.

But weather is massive, especially wind,
But weather is massive, especially wind,

but dryness is huge too.
but dryness is huge too.

And firefighters do a lot of training classes
And firefighters do a lot of training classes

to understand the weather and what the weather does to fire,
to understand the weather and what the weather does to fire,

and also to identify cues that they can look for
and also to identify cues that they can look for

that might tell them of like impending hazardous conditions.
that might tell them of like impending hazardous conditions.

- Okay so, we know that fires can create wind, lightning
- Okay so, we know that fires can create wind, lightning

and even rain.
and even rain.

We also know that weather is the most important factor
We also know that weather is the most important factor

in fire severity.
in fire severity.

High wind on a hot day with low humidity means that any fire
High wind on a hot day with low humidity means that any fire

that starts is gonna be extremely difficult
that starts is gonna be extremely difficult

or impossible to put out.
or impossible to put out.

And as the climate warms, there are more hot,
And as the climate warms, there are more hot,

dry days and more fire.
dry days and more fire.

Now here's the good news.
Now here's the good news.

All that fire is not anywhere near as bad for the climate
All that fire is not anywhere near as bad for the climate

as we once thought.
as we once thought.

It might look like the smoke coming out of a power plant
It might look like the smoke coming out of a power plant

when we see these big smoke columns stretching 20,000 feet
when we see these big smoke columns stretching 20,000 feet

into the sky. But Dr. Lisa Ellsworth
into the sky. But Dr. Lisa Ellsworth

and her team did some fascinating research
and her team did some fascinating research

in a fire burned area in Oregon.
in a fire burned area in Oregon.

And her findings were surprising.
And her findings were surprising.

- We have a plot up there and we have one down there.
- We have a plot up there and we have one down there.

And then we have one kind of at the end there
And then we have one kind of at the end there

where it wraps around.
where it wraps around.

- [Maiya] We know trees store carbon through photosynthesis
- [Maiya] We know trees store carbon through photosynthesis

as they take it out of the air
as they take it out of the air

and use it as a building block to grow.
and use it as a building block to grow.

But Lisa's work sheds light on what happens to that carbon
But Lisa's work sheds light on what happens to that carbon

after a fire.
after a fire.

- We were out in these plots for two summers,
- We were out in these plots for two summers,

and we measured every single piece of burnable material
and we measured every single piece of burnable material

that's out here,
that's out here,

every piece of carbon that's out here.
every piece of carbon that's out here.

(calm music)
(calm music)

You can tell there's a lot of large wood on the ground.
You can tell there's a lot of large wood on the ground.

It's hard to find somewhere to step.
It's hard to find somewhere to step.

So most of the carbon, it's still stored here on this site,
So most of the carbon, it's still stored here on this site,

The fine fuels, the grasses
The fine fuels, the grasses

and the needles would have burned up.
and the needles would have burned up.

But the vast majority of the biomass is in these big chunks.
But the vast majority of the biomass is in these big chunks.

And these big chunks are still here.
And these big chunks are still here.

They're still storing carbon.
They're still storing carbon.

So up here, we have a patch of this fire
So up here, we have a patch of this fire

that burned with very low severity.
that burned with very low severity.

And we measured those patches as well in the exact same way,
And we measured those patches as well in the exact same way,

and found that there's really the same amount
and found that there's really the same amount

of carbon storage in the low severity parts
of carbon storage in the low severity parts

as there were in the highest severity parts,
as there were in the highest severity parts,

because all of the parts of the tree are still here on site.
because all of the parts of the tree are still here on site.

- And other researchers have found
- And other researchers have found

that wildfires release around 20% or less
that wildfires release around 20% or less

of the carbon stored in a forest,
of the carbon stored in a forest,

meaning that as long as they're left alone,
meaning that as long as they're left alone,

burned forests continue to store carbon
burned forests continue to store carbon

that otherwise might be a greenhouse gas in the atmosphere.
that otherwise might be a greenhouse gas in the atmosphere.

But I wanted to see this for myself.
But I wanted to see this for myself.

Oh my goodness.
Oh my goodness.

Look at this.
Look at this.

I mean, I can't imagine Lisa and her team
I mean, I can't imagine Lisa and her team

actually like wading through all of this brush here
actually like wading through all of this brush here

to measure the tree trunks, the bush underneath.
to measure the tree trunks, the bush underneath.

Measuring all that carbon and finding
Measuring all that carbon and finding

that it is holding the same amount as this old growth forest
that it is holding the same amount as this old growth forest

to the left.
to the left.

When I think of a burnt forest, I think of just,
When I think of a burnt forest, I think of just,

like everything's gone, everything's just burnt down.
like everything's gone, everything's just burnt down.

There's just like dirt leftover.
There's just like dirt leftover.

So for me, it's kind of surprising
So for me, it's kind of surprising

to see you still have these trees still standing.
to see you still have these trees still standing.

It makes sense that this tree would hold
It makes sense that this tree would hold

as much carbon as that tree
as much carbon as that tree

because really it's just the branches that are gone,
because really it's just the branches that are gone,

and you have this new growth here.
and you have this new growth here.

So that definitely makes sense.
So that definitely makes sense.

That definitely makes sense to me.
That definitely makes sense to me.

(calm piano music)
(calm piano music)

Still, the danger of fires posed to us is real.
Still, the danger of fires posed to us is real.

Nearly half of the country was covered
Nearly half of the country was covered

in thick smoke last summer.
in thick smoke last summer.

And if you were in a smoky area,
And if you were in a smoky area,

you probably remember that respirator mask
you probably remember that respirator mask

and HVAC filters were suddenly sold out everywhere.
and HVAC filters were suddenly sold out everywhere.

So before the fire comes,
So before the fire comes,

think of everything you wish you had,
think of everything you wish you had,

but couldn't get and go stock up as best as you can.
but couldn't get and go stock up as best as you can.

A great way to filter smoke in your house
A great way to filter smoke in your house

is to take an HVAC filter
is to take an HVAC filter

and put it on one side of a box fan.
and put it on one side of a box fan.

Simple, cheap, and it works.
Simple, cheap, and it works.

All right, thanks for watching.
All right, thanks for watching.

If you enjoyed this episode, give us a like,
If you enjoyed this episode, give us a like,

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