The Science of Wildfires: Why They're Getting Worse | WSJ

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It was just a fireball,
and it traveled so fast.

I just saw flames

all up on the hill behind my house.

It was Armageddon, I'll tell you.

The fire coming in
and burning all around us.

(narrator) Alaska, Arizona,
California, Montana, Oregon,

Australia, Brazil,
Canada, Greece, Russia--

these are just some of the places
where in recent years

wildfires have raged out of control.

NASA satellites detect

more than a million large fires
worldwide every year.

(Doug) The Western United States,
for example, has seen larger fires

in each of the last several years

and more intense burning,

and many times those fires spread faster,

making them more difficult to put out

and more dangerous for the communities
who live in that vicinity.

(narrator) In many cases,
the blazes are set by human activity,

but sometimes policy fuels the flames too.

Consider California.

The state's forests are overgrown

in part because of past federal policies
of putting out wildfires

rather than letting them burn.

Some of these policies were enacted
in response to a devastating fire in 1910,

in which millions of acres burned
and more than 80 people died.

Years passed, and suppression
became the go-to strategy

for dealing with fire.

(reporter) It only takes a minute
to wipe out a century.

(narrator) Initiatives like Smokey Bear

urged Americans
to help prevent forest fires.

(Smokey Bear) Only you
can prevent forest fires.

(narrator) In 1974, Congress passed

the Federal Fire Prevention
and Control Act

in an effort to save lives,

and that plan worked.

Around that time, according to the Act,

fires of all types killed
more than 12,000 people each year.

Today, according to
the U.S. Fire Administration,

the death toll is lower,

but...

(Doug) Part of the reason
we see increasing fuels

and increasing extreme fire behavior

is that we have a legacy
of putting fires out

and allowing fuels to grow,

permitting fires when they do start
to get out of control,

(narrator) Overgrown forests
have an abundance

of small and medium trees,
known as ladder fuels,

which can make fires more dangerous.

Ladder fuels would allow a surface fire

burning often slowly along the ground

to transition into the canopy

where it can spread more rapidly.

And when those trees are burning,

the embers that are blown by the wind
can ignite the neighboring trees

that can also be spread further downwind.

(narrator) That's part of the story
of California's 2018 fire season.

The deadly campfire
was fed by dry weather,

fast winds, and ladder fuels.

According to recent research,

20 million acres of forest land
or nearly 20% of California

would benefit from what's known
as fuel treatments.

Land managers can limit the fuels

that could create large,
fast-moving fires

in several ways,

including getting out vegetation--

think logging or clearing brush--

prescribed burns
where small fires are set deliberately,

or letting natural wildfires
in unpopulated areas

run their course under the watch
of local firefighters.

But clearing out brush
can be expensive and labor-intensive.

First, many of these trees
are small in diameter,

so they don't have
commercial value as timber

and there's little financial incentive
to remove them,

and federal policies
have historically favored

putting out fires as soon as they start,

to keep people safe.

Maintaining that balance

of different ecosystem types
and different fire frequencies

is more difficult when we move into areas

with more dense human populations.

And so the wild land urban interface

is really where these two challenges meet,

where people are living in communities

against landscapes
that historically have had fire activity.

Those are landscapes
that are very difficult to protect

when fires do start.

(narrator) One of the factors
affecting California's wildfire season

is new housing construction
in fire prone areas.

Climate change is adding
to the problem too.

(Doug) Where fuels are abundant today

and where climate change is leading
to warmer and drier conditions,

we are already seeing
more extreme fire behavior.

(narrator) According
to recent federal data,

the last decade was the warmest on record.

During the summer of 2020,

fires burned in the Arctic,

as parts of Siberia broke the record

for the highest temperature ever recorded
above the Arctic Circle.

They're almost always too cold
and too wet to burn.

So, as those landscapes,

which are warming three times faster
than the rest of the planet,

continue to warm and dry,

we certainly expect to see more fires

in those remote landscapes

directly in response to climate change.

(narrator) In August of 2020, wildfires,
most of them sparked by lightning,

raged out of control across California.

Earlier in the year, state officials
had warned of high fire danger

caused by a dry winter and warm spring.

It's a pattern scientists
generally attribute to climate change.

In May, the mountain snowpack
in California, Sierra Nevada

was just 13% of normal.

And it's not just 2020.

Half of California's
20 most destructive wildfires

have happened since 2015.

Across the forests of Southeast Australia,

NASA mapped more fires
between 2019 and 2020

than they had in the last 16 years.

The fires were fueled
by extreme heat and drought.

Hotter, drier weather

sucks moisture out of the trees,
grasses, and other fuels,

making them more flammable.

And this is making fire management
all the more complicated.

So as conditions that allow
wildfires to spread

are lasting longer across
the United States and elsewhere,

there's a shorter and shorter window

where active management
could happen under conditions

that wouldn't risk fires
escaping and spreading

into lands as a wildfire.

(narrator) That means
fighting fire with fire

might not be an option
for certain regions anymore.

So to help with wildfires,

researchers are working on algorithms

to improve forecasting.

(Doug) If we can anticipate the timescales

and the locations
where fires are most likely,

we have the best chance of trying
to mobilize and prepare resources

to anticipate fires
and make a more timely decision

about which fires to put out
and which to let burn.

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