(wind whirring) - [Narrator] Small whirling cyclones of dust.

You've probably seen them meandering through farms or open fields.

(gentle music) They can grow anywhere from a few feet in diameter to the size of a school bus, and the really big ones can reach a half mile high.

But this isn't a mini tornado.

It's a dust devil.

- People always want to know what is it like to be inside of a dust devil.

And the answer is, dusty.

(laughs) (wind whirring) - [Narrator] This kid in Jacksonville, Florida, found that out the hard way.

Dust devils are surprisingly common on baseball fields, and dirt roads, and deserts.

Common theme?

Dust.

But what exactly is a dust devil?

- So a dust devil is a small scale dry vortex.

It's a whirlwind.

It's lifting dust up into the atmosphere.

But exactly how the dust gets lifted from the surface, exactly what are the conditions that give rise to dust devils and what conditions don't give rise to dust devils, we just don't really understand all of that.

- [Narrator] Brian Jackson's eager to learn more about how dust devils work, so he's joined a team of scientists in the Alvord Desert, a 12 x 7 mile wide playa.

It's dry, hot, and dusty.

The perfect playground for studying dust devils.

(indistinct chattering) - We are trying to catch a dust devil.

So we've got a net, which is made up of these little wind sensors.

If a dust devil swings by and goes through part or hopefully all of this grid, then every one of these sensors is going to register something different.

So it's kind of like if each of these was a pixel in your camera, we're trying to take a picture of the dust devil as it goes on by, or make a movie of even.

(footsteps tapping) - [Brian] There you go, right there.

(tripod rattles) - [Narrator] It's late morning and as the temperature rises, the dust devils will become active.

(tripod thuds) (wind whirring) - That's kind of a little lazy one, isn't it?

So how does the dust devil actually work?

Well, the short answer is we don't know exactly.

That's one of the reasons we're out here is trying to understand that.

But we understand the basic mechanisms behind dust devils.

The air close to the ground will get heated by the surface.

That will make the air at the ground very hot and that makes it buoyant.

So it wants to rise like a hot air balloon.

And as that air begins to rise, it sucks other air in around it.

And as that air gets sucked in, oftentimes it'll start to spin up.

And if you get just the right conditions and just the right amount of dust around, then that spinning air can lift the dust up off the surface and then entrain it into that sort of convective vortex and lift it up into the air.

- [Narrator] Dust devils are mostly harmless.

At least the small ones.

- Dust devils typically are not a dangerous thing.

They're not like tornadoes.

They're much smaller in scale.

The winds are much weaker.

But, you know, you'll get grit in your eyes and your teeth, that kind of thing.

Alright, that looks good.

We've got our network set up now.

We've got a miniature weather station set up behind me here, and so now we just, it's kind of a waiting game.

We got to wait for some dust devils to blow through.

(wind gusting) - Yeah.

- [Narrator] The data they collect will broaden their understanding of dust devils on Earth, but these scientists are much more interested in dust devils that are nearly impossible to study in-person, because they're about 170 million miles away.

(mellow music) - What's really invigorated the study of dust devils are our observations on the planet Mars, where dust devils occur quite frequently.

- [Lori] So Mars has big dust devils all over the entire planet, so there's dust devils everywhere.

Some of them get gigantic, like a kilometer wide, way bigger than anything you'll see here.

- [Narrator] Okay, so there's a lot of dust devils on Mars, but why does it matter?

Why study them in the first place?

- [Ralph] It's important that we understand their role in the Martian climate, how much dust they can lift, how much they change the reflectivity of the surface, and also how they influence the operation of vehicles on Mars by clearing their solar panels.

- Dust devils probably are a major contributor to the climate on Mars.

Dust suspended in the atmosphere of Mars acts a little bit like a greenhouse warming gas, but because we don't understand exactly how dust devils work, it's very hard to make predictions and assessments.

So, we're out here on the Alvord Desert to try to study terrestrial dust devils as an analog to understand Martian dust devils.

(wind whirring) (Brian groans) Well, it's very windy today!

A little wind is good for dust devils.

A lot of wind is probably not good for dust devils, so we might get too much wind action today for dust devils.

We'll see.

- [Narrator] The dust devils that are forming are mostly on the other side of the playa.

- Studying dust devils can be quite tricky.

We don't understand the processes behind them well enough to say, "Okay, if we park our vehicles here and set up our instruments here, we're going to catch 50 dust devils today."

We might do that and see them all on the horizon and only get one or two, and consider ourselves lucky for getting those two.

- Oh, there's another one right behind us.

One thing to think about is like, how many dust devils have we missed by like 30 feet- - Oh yeah.

- Or something?

(wind whirring) - [Narrator] Finally, a dust devil travels right through their grid.

(wind whirring continues) (Brian coughs) (mellow music) - Yeah, that's what we came for.

- [Narrator] The team only catches a few dust devils on this trip, but that's enough to give them valuable data and brings them one step closer to understanding how these mysterious whirlwinds truly work.

And the more they learn about dust devils on Earth, the better prepared they'll be for future missions on Mars.

- [Swati] Perseverance is safely on the surface of Mars ready to begin seeking the signs of past life.

(wind whirring) - Getting inspiration for your next adventure.

It's kind of why you're here, right?

(upbeat music) Well, you can support more of what we do on "Oregon Field Guide" and everything else you see on OPB by going to opb.org/video and becoming a sustaining member.

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