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- Tornado is right behind us is crossing right here.
(powerful music playing)
(strong wind blowing)
- Tornadoes are among the most violent
natural phenomenon on earth.
And despite decades of study,
there are still a lot of questions
that have yet to be answered.
But what we can observe about them is fascinating.
They're found on every continent except Antarctica
but the U.S has larger tornadoes
and more of them than anywhere else on earth.
And if you think you know where the
riskiest areas are,
pay attention because tornado frequency
is actually shifting East from Texas
towards the Southeast U.S.
In this episode, we'll visit a Kansas town
hit by a Supercell tornado.
Follow a storm-chasing meteorologists,
and as always,
learn what you can do to prepare your home
and stay safe.
(strong wind blowing) (debris crashing)
So how does a tornado form?
First, warm moist air near the earth surface rises
and develops into Cumulus clouds.
If the atmosphere is unstable,
this warm air continues to rise
and the cycle of cloud formation continues
and a thunderstorm is formed.
When wind speeds and directions are different
at different altitudes,
it's called wind shear.
And that wind shear can cause a horizontal
rotating tube of air to form.
Then the rising warm air called an updraft
can turn that horizontal to vertical
making the whole storm rotate.
At that stage, the storm is considered a Supercell.
Warm moist air pushes upward,
while cool dry air pushes down.
And these two forces tighten
and the vortex is sent towards the ground.
While all super cells have the potential
to produce a tornado,
only one in five do end up creating one
and exactly which ones will become a tornado,
and which ones won't remains a mystery
and a weakness in our forecasting
and warning systems.
But that's where the work of meteorologists
like Nick Stewart comes in.
- So we're trying to figure out
why one storm will produce a tornado
and why another one will not.
And the biggest problem is we don't have data
right around those tornadoes.
So what we're trying to do is place
weather instruments out ahead of the storm,
around the entire storm to see exactly
what's happening with the temperatures,
the humidity values
in those lowest levels of the storm.
So on May 28th, 2019,
we knew that there was going to be severe weather
in Eastern Kansas.
That blue right there,
That's gotta be a trail on the ground.
We knew that it was a very strong tornado based on radar.
We knew winds were easily 140, 150 miles an hour
if not stronger.
And we knew it's very large, but we knew that we
were in the perfect spot
to put a weather instrument.
And you're basically playing a game of cat and mouse
with tornadoes, trying to make sure you get in
the right spot at the right time.
On the far right side of this rain
you can see the inflow tab blowing into it.
Thete the very, probably strong tornado
is in all of that rain right there.
And we've never had an example
of a tornado being that large before.
(strong wind blowing)
- [Randy] Big time tornado, Nick hurry.
(car engine sound)
- [Nick] And this tornado begins
just accelerating towards us.
And at that point,
the outer rain bands are basically
right overhead of us.
And we need to go.
- [Randy] Hey, we gotta go.
Nick, we gotta go.
(strong wind blowing)
- [Nick] Go, go, go.
And you can just see the tornado take almost
a direct aim, right at Linwood.
- [Nick] Tornado is right behind us
crossing right here.
- [Randy] Linwood's next.
Linwood's going to get it
If it keeps that track.
- [Maiya] Residents of Linwood received tornado warnings
and took shelter.
- [Josh] God, it's huge too.
(strong wind blowing)
It's here, we're headed to the basement
(tornado wind hustling)
- [Jessica] We're okay. We're okay.
- [Josh] Everything's good right now.
- [Jessica] Yup. We are okay.
- [Josh] the pressure that was on your head,
it felt like it pushed your head in a quarter
of an inch and then it blew back out.
And we knew when that blew back out,
that was the house coming apart.
- [Josh] Oh my God.
Well, we got out in basement right in time.
This is, - [Jessica] Oh my God..
- [Josh] this is what my parents' kitchen was.
(slow piano music)
I mean, we were a direct hit,
but we're alive.
- [Maiya] In all 19 houses were destroyed
and 50 were damaged.
Tornadoes are rated on the
enhanced Fujita or EF scale
EF-0's cause light damage and have winds
of 65 to 85 miles an hour.
While EF-5's have winds over 200 miles an hour
and cause incredible damage.
The tornado that hit Linwood was an EF-4
and it was a mile wide.
but because of early warnings,
no lives were lost.
(piano music playing)
- [Maiya] Elaina Sutley is a structural engineer
whose goal is to prevent the kind
of devastation that we saw in Linwood.
- [Elaina] So the tornado landed at about 6:00 PM
on Tuesday, May 28th.
We were on the ground at 7:00 AM
that Friday the 31st.
Our goal was to document
and understand the extent
of damage that happened along the path
specifically from a structural engineering perspective.
And we paired off into our teams of two
and we all had a map
with the survey points on our map
and everyone was assigned specific areas to go to.
In our damage assessment,
we consistently saw evidence of a lack
of a continuous load path where the roof was not
properly connected to the walls
and the walls not being completely connected
to the foundation.
In a few select cases,
we did see where interior walls were only glued
to the foundation.
And when we approached this site
the slab had been swept clean, and
that all of the built structure
had been completely lifted off and removed,
but there was just debris everywhere.
And so now they're rebuilding,
there's still no adopted building code
in Leavenworth County.
So this is their walk-out basement.
And if you have a basement,
that's a great place to shelter.
But all of this subfloor down here
had been lifted off by the tornado.
When you're reaching EF-4 intensity speed,
you can still be sucked out of it.
And so at that point, you really need a safe room.
So the people who lived here did shelter in their safe room.
Had they been out here, they probably would
have been sucked up by the tornado and killed.
Our building codes don't include tornado loads.
We do not design structures
to withstand tornadoes.
So we expect to see catastrophic damage
when a tornado comes through.
This is hard for me to understand
because we have more than 1,200 tornadoes
documented every single year
in the United States and have a history
of more than 4,300 documented
in the state of Kansas.
But tornadoes are not in our building codes.
- The good news is that houses can be easily
and affordably built to withstand many tornadoes
and it's possible to retrofit existing structures.
You can really see why this matters
by looking at research from our friends at IBHS.
If you've seen our episodes on fires or hurricanes,
you remember that they build and destroy homes
in their labs to figure out weak points
including creating tornado winds.
For your home to stay put
when it's faced with tornadic winds,
it's all about the connections.
Your walls need to be bolted to the foundation.
The stories of your house needs to be tied together.
And the roof needs to be tied down to the walls.
This might seem obvious but without building codes,
you often find houses without any of these connections.
So, to test this design,
researchers at IBHS built two houses.
One included fortified standards,
and one did not.
(strong wind blowing)
I think I know which one I'd rather be in
during a tornado.
(debris crashing)
Even if you live in a well-prepared home,
make sure you have a plan in place
when tornado weather is coming your way.
- The tornado watch is issued,
that's when you want to make sure your weather radio is on.
You want to have a way to get multiple ways
of getting warning.
If that warning is issued,
the biggest thing is respect the polygon.
If you're inside that tornado warning
treat it as if it's coming your way.
- [Maiya] If you're able to afford it,
a concrete, safe room is the best option
as it should protect you
from even the most powerful tornadoes.
But whatever your shelter,
makes sure it's cleaned out
and that you have easy access to it.
- For most people, the basement's the best place to go.
And the lowest level of your home
it'll protect you from any flying debris
outside during a tornado.
If you don't have a basement,
if you have like a closet
or a bathroom
or underneath stairs
the biggest thing is just putting as many walls
between you and the outside as possible.
- Finally, if you have a reasonably safe place,
don't evacuate.
But if you live in a mobile home
or similar structure,
make an evacuation plan.
Pay close attention to weather updates
and go early to a predetermined place
like a school, church or a neighbor's house
and give yourself plenty of time to get there
and make absolutely sure that you have access to it
when you need it.
The last thing you want is to be stuck
in the car when a tornado is coming your way.
So make a plan.
And if you want to see more of
the amazing research at the IBHS lab,
check out our fire and hurricane episodes.
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