So, I think all good tornado talks
need to start with an awesome tornado shot.
And this is not that tornado shot.
Alright, that was the first tornado I ever saw,
and it was really cool,
and it was really scary,
and the reason I'm showing it to you guys
was because that's why I got into the field
in the first place.
So, even though it's a bad photograph,
it was really cool to be out there the first time.
But now I'm taking real tornado footage.
Fast forward a few years here.
This is a few years ago
during a field project called Vortex 2,
where myself and a bunch of other scientists
were out there
surrounding tornadoes with different types of instrumentation
and trying to figure out how tornadoes form.
So, it's a big question
that we're trying to answer.
It sounds like a basic one,
but it's something we're still trying to figure out.
We're also still trying to figure out
what the winds are like near the surface.
We know what the winds are like above building level,
but we really don't know what the winds are like
at the surface
and how that relates
to what we're seeing above building level.
So, most tornadoes form from what we call supercell thunderstorms,
and these supercell thunderstorms
are what you commonly think of as
tornado-racing storms.
They're big, rotating thunderstorms
that happen a lot in the mid section of the United States.
But the problem is
even because they're rotating up above
doesn't mean they're rotating at the surface.
And when we look at these storms
and when we look at these pictures
and when we look at the data that we have
they all kind of look the same.
And it's really problematic
if we're trying to make tornado forecasts or tornado warnings
because we only want to warn on the storms
or forecast on the storms
that are going to actually make a tornado.
One of the big critical distinguishing features
that we think between these storms
is something about the rear flank down draft.
So, these big rotating thunderstorms
have this down draft that wraps around the rear edge of it,
hence the rear-flanking down draft.
But we think how warm that is,
how buoyant that air is,
and then also how strong the updraft
that's wrapping into
makes a big difference on whether or not
there's going to make a tornado or not.
And there's certainly a lot more that goes into it
and I'll tell you a little more about that in a second.
Once you actually get a tornado,
again, the problem that we have
is getting measurements near the surface.
It's really hard to get measurements near the surface
because most people don't want to drive into tornadoes.
There are a few exceptions,
and you might have seen them on TV shows.
But most people don't want to do that.
And even getting instrumentation in the path of the tornado
is pretty tricky, too
because, again, you don't want to be that close to a tornado
because sometimes the winds around the tornado are strong, as well.
So, getting information,
that critical location,
is key for us
because, again, we don't know
if the winds that we're seeing above ground level,
way above building level,
actually map to the surface.
if they're stronger, if they're weaker,
or if they're about the same as what we're saying above buildings.
The way that we get at answering a lot of these questions,
and I'm an observationalist, so I love to get out in the field,
I love to collect data on tornadoes,
we compile a lot of observations.
And I work with this group who operates these mobile radars,
and they're exactly what they say they are:
they're basically a radar on the back
of a big blue truck,
and we drive up really close to tornadoes
to map out the winds, we map out the precipitation,
we map out all these different things that are going on
in order to better understand the processes in these storms.
And that bottom there,
that's what a tornado looks like
when you're looking at it with a mobile radar
and when you're looking at it with a mobile radar real close.
Also, we do a lot of modelling,
so we do a lot of computer models and simulations
because the atmosphere is governed by the laws of physics,
so we can model the laws of physics
and see where the tornado might go,
where the storm might go,
how strong the winds are near the surface
and not actually have to go out in the field.
But, of course, we want to have both
observations and modelling
to move forward with the science.
So, this is,
we showed you that video earlier
that went real quick, too.
This is what it looks like when you look at it with a radar.
So you saw it visually,
but this is what I get really excited about
when I see now in the field
is stuff like this.
And the really exciting thing about
looking at stuff like this
is that this storm,
we caught it from when it didn't make a tornado
to when it made a tornado
to when it intensified
to when it disappeared.
So, this is the one of the really rare data sets
that we have out there
that we're able to study the entire life cycle of a tornado.
I talked about that rear-flying down draft,
how we think that rear-flying down draft is important
because it tilts, there's a lot of spin in the atmosphere,
but the problem with all this spin in the atmosphere
is it needs to be oriented vertically
because that's what tornadoes are doing,
and it needs to orientated vertically
near the ground.
So, we think this rear-flying downdraft,
we think that it just pulses,
and these pulses in this rear-flying draft,
we think are very important
for converging that rotation
and also getting that rotation in the right place.
Other things that we've learned
is that we have gotten a bunch of fortuitous measurements
in the path of the tornadoes
and very near the surface.
And we found out that the winds near the surface
are actually pretty comparable
to what we're seeing 30 to 40 meters above ground level,
so there's not a big reduction in what we're seeing
above the surface to what we're seeing at house level.
And that was a pretty surprising finding for us
because we kind of assumed
the winds decreased pretty substantially near the surface.
So I'm going to end it with this real quick.
This is not the last tornado I ever saw,
but I really like this image
because it was taken with one of those mobile radars I was talking about.
And this is a tornado, not a hurricane,
and this is what it looks like
when you're really close to it.
And I find this amazing,
that we can actually take technology,
take technology this close to these types of storms,
and see this inner workings.
And for those of you who look at tornado images often,
you can see there's a lot going on there.
There's rain spiraling,
and you can actually see the debris cloud
associated with this tornado,
and I look forward to the future
and future technologies
and being able to learn a lot more about these storms
as the world advances
and you guys contribute to the science
and we're able to really learn how tornadoes form.
Thank you!