When I posted the awesome video of a fire tornado last week, I had only heard rumors of such things. Apparently, they’re more common than I thought.
Here’s another amazing video, and this one is even better: it’s longer, and you can see the rotating smoke cloud around the column of fire!
This really is a fantastic demonstration of how microscale weather works. Imagine: a fire starts. As the air is heated above the fire, it rises, and the upward motion can be very strong. This leaves a lower pressure spot at the fire, and the air from outside the fire rushes in to fill the gap. The air is very turbulent, and as the inward-moving air from one side hits air coming in from the other, swirls can form. These get amplified by the constant gale of air, and rotation on a larger scale can get started and sustained. The whirlwind gets pumped by the hot air rising, and the next thing you know you’ve got a full-blown tornado of fire.
Watch the video; see how the fire tornado is narrow and well-focused, but the air outside it is rotating more slowly? That’s an outcome of a law of physics called the conservation of angular momentum: if you take something that’s spinning and shrink it, the rotation rate will increase. You’ve seen this a bazillion times; figure skaters start spinning, then draw their arms in. Their decreased radius increases their spin, sometimes very dramatically. Water draining out of a bathtub does the same thing, too.
We see it in astronomy all the time too: massive stars undergo core collapse at the ends of their lives. The core shrinks so much the spin rate can go up vastly, and we’re left with collapsed neutron stars — mind-numbingly über-dense objects with the mass of the Sun compressed into a ball only a few kilometers across, and they’re spinning quite literally a thousand times per second: faster than the blades of a kitchen blender.
Angular momentum is a powerful, powerful thing. And it’s also beautiful. On scales as titanic as an octillion tons of star matter collapsing to form a weird quantum mechanical fluid, down to an almost supernaturally awe-inspiring column of fire, physics is everywhere, and it’s an astonishing thing to watch.
Tip o’ the fireman’s helmet to Dave Mosher.
August 30th, 2010 at 12:32 pm
We need a World of Warcraft mage spell that has this effect!
August 30th, 2010 at 12:41 pm
Is this a “fire-tornado”? Or more properly called a ‘fire-devil” as the mechanism is more like a dust-devil?
I drive that road a few times a week on the way to the summit, going to be depressing to see the damage up-close tomorrow. A lot of burned native mamane.
August 30th, 2010 at 12:46 pm
Aloha Phil…
Yes, that fire was a doozy. You might be interested to note that the fire in question was on the flanks of Mauna Kea – the same mountain here on the Big Island that is home to over 12 world class telescopes (disclaimer, I work for Subaru Telescope).
The fire never threatened the observatories (mainly because they are at 13,000 ft, so way above any vegetation), however, it did come within 10 miles of Hale P0haku, where the visiting scientists and night crews stay at the 9000 ft level.
The fire also closed Saddle road, the only road that bisects the island and the only access road for the summit personnel to access the observatories (however, while the public was denied access to the summit, the scientists were allowed through as long as they were in a company vehicle or had an observatory business card).
One person was arrested on suspicions that he started the fire. The outcome is still pending.
As of this moment, the fire is 70% contained and the summit is fully open to everyone.
August 30th, 2010 at 12:52 pm
Kind of like the firestorms during the bombardments on German cities during WW2. First noticed in Hamburg and brought to its frightful perfection in Dresden and quite number of Japanese cities. Same effect, only on a larger scale: The fires heated the air which rose, the resulting low pressure zone drew large amount of air, which cool oxygen only fed the fires even more. Result was people literally suffocating and their bodies incinerated in the air raid shelters…
August 30th, 2010 at 1:06 pm
Just a quibble about the rapidly-rotating neutron stars: usually the end result of collapsing stars is a neutron star that spins about once per second (compare to the sun, which spins about once per month). The ones that spin ~a thousand times per second acquire further angular momentum, probably by accreting material from binary companions.
[TMB]
August 30th, 2010 at 1:33 pm
Use to see a lot of these at the fire grounds at Texas A&M at fire school but they only reached 60 70 feet because of limited fire base and we put out the energy engine anyway
August 30th, 2010 at 1:44 pm
I’m waiting for a tornado made of grated cheddar. That would be delicious.
August 30th, 2010 at 2:07 pm
That may be bigger than any of the fire devils I’ve seen at Burning Man.
August 30th, 2010 at 2:08 pm
Or a Tournedo Tornado. Then it could collide and meld into the fire-tornado. Best- Smelling. Destruction. Ever.
August 30th, 2010 at 2:25 pm
When I see this video it conjures up images of natives hundreds of years ago seeing such a sight and only being able to conclude that the gods themselves have risen from the ground.
Truly a spectacular sight.
August 30th, 2010 at 3:31 pm
A tornado made of bunnies! Run!
August 30th, 2010 at 3:35 pm
[...] http://blogs.discovermagazine.com/badastronomy/2010/08/30/another-tornado-made-of-fire-waiting-now-f... [...]
August 30th, 2010 at 3:54 pm
@Ricardo — kinda like Exodus….
August 30th, 2010 at 4:09 pm
This also shows the larger structure of the dust-devil fairly well. The core is small, but there’s a large column of smoke/air that is entrained/tags along with the core.
They do all kinds of strange things in the air: sometimes they split into a Y-shaped structure with two or more cores; more commonly they simply stop and flatten out if they hit the top of an inversion.
And yes, sometimes they are powerful enough to entrain bugs (tho’ not grasshoppers that I’ve (yet) seen). Thermals (dust devils to ground lubbers) can often be found by looking for hawks or other soaring birds. Less commonly, they can be found by noticing swallows or martins at high altitudes: this only happens when a dust devil is powerful enough to suck up bugs, and the birds follow their food. Both of these are useful to soaring pilots in search of “lift” (rising air in which to climb).
Phil, you live in some of the best soaring country in North America. I recommend you try it out sometime, unless you’re prone to airsickness.
August 30th, 2010 at 4:33 pm
Note also the multiple suction vortices rotating around the smoke funnel’s core – just like in a normal everyday non-fire tornado:
http://en.wikipedia.org/wiki/Multiple_vortex_tornado
August 30th, 2010 at 4:45 pm
For more, log onto http://www.tornadoproject.com
Tom Grazulis does a lot better job with his tornado video classics than the weather channel does.
frankly, I miss AM Weather with Carl Weiss and Joan van Ahn
August 30th, 2010 at 4:48 pm
P.S.: it doesn’t take strong winds to create these, nor are strong winds responsible for their structure. Rather, strong winds tend to break up dust-devils; they pick up their swirling character with or without strong winds.
I’m not aware of any substantial bias in the direction of the swirls, but that doesn’t mean that there isn’t one. Yes, I have soared south of the equator.
[Note: I've also posted as 'eyesoars'.]
August 30th, 2010 at 5:11 pm
Wow, this tornado was definately a crazy one. Never seen anything like it.
August 30th, 2010 at 6:22 pm
Repent! The end is nigh! About goddamn time too. Don’t think we’ll make 2012…
August 30th, 2010 at 6:29 pm
Wild info and video. Thanks!
August 30th, 2010 at 6:29 pm
@7. Itzac,
Grated cheddar, salsa and corn chips! It’s hot, destructive and burns your tongue! Then you need beer.
August 30th, 2010 at 7:01 pm
In college, I worked summers in a cannery. One night I worked a line of vats where water was boiled off tomato paste to make ketchup. When the wind over the vents was just right, there would be a perfectly cylindrical vortex of steam about 10 cm in diameter rising off the surface.
I saw a vortex of a different sort in the Army. One autumn day I stepped outside and saw three gigantic rotating columns of storks riding thermals. There were hundreds in each column. The columns were 100 yards or so across and at least a quarter mile high. Unfortunately I was working in a classified area and didn’t have my camera. And I never saw it again.
August 30th, 2010 at 7:01 pm
I couldn’t help but notice that even the firefighters got the hell out of there.
August 30th, 2010 at 7:09 pm
Well thats cute how bout this one
Great Kanto Earthquake
The earthquake struck at lunchtime when many people were using fire to cook food, the damage and the number of fatalities were augmented due to fires which broke out in numerous locations. These fires spread rapidly due to high winds from a nearby typhoon off the coast of Noto Peninsula in Northern Japan and some developed into firestorms which swept across cities. This caused many to die when their feet got stuck in melting tarmac; however, the single greatest loss of life occurred when approximately 38,000 people packed into an open space at the Rikugun Honjo Hifukusho (Former Army Clothing Depot) in downtown Tokyo were incinerated by a firestorm-induced fire whirl.
Now that was blazenado.
August 30th, 2010 at 10:48 pm
The first fire tornado you posted about made Yahoo news a day or so later. I was disappointed with the amount of people commenting on Yahoo’s board about the fire tornado being some kind of message from a God. Worse, many were saying it was a sign of the end of times.
I’m sure this additional fire tornado will only add fuel to their fires. Pun intended.
I worry for the people of Earth when the citizens of one of the best educated countries in the world still blame easily explained, natural phenomena on God.
August 30th, 2010 at 11:15 pm
Steve D:
You can also see something similar to your storks at Hawk Mountain, PA during the fall migration. Hawks and vultures migrating south will congregate in ‘kettles’ (thermals) as they come over the mountain, often with dozens or more birds apiece, particularly on sunny days with good cumulus clouds.
http://en.wikipedia.org/wiki/Hawk_Mountain
August 31st, 2010 at 12:30 am
Really nice, clean video illustrating the effect well, in isolation.
We get this phenomenon during bushfires here on Australia, but rarely so distinct. Usually there’s dozens (or hundreds) lasting seconds rather than minutes.
Some are rather bigger though. They’re scary.
August 31st, 2010 at 2:21 am
This year Australia has been unusually wet and the whole country is currently beautiful and green. Which means when summer comes we will probably have more than the usual numbers of locusts swarming to feed and grow from the plant growth.
Which means Phil’s wish of a locust tornado might just come true.
The terrible fires in Victoria last year were probably subject to this fire tornado phenomena. One witness who lived on one side of a valley reported what he described as a flaming giant taking steps and touching down (and setting further fire to) properties on the other side of the valley. When these tornadoes (steps) touched down they destroyed everything. Houses, people, the lot. Even those supposedly fully prepared for bushfires.
August 31st, 2010 at 2:24 am
That is, uh, cool.
August 31st, 2010 at 7:40 am
I saw a vortex of a different sort in the Army. One autumn day I stepped outside and saw three gigantic rotating columns of storks riding thermals.
Hello Steve D,
in which part of the world did You see that stork “tornados”?
Such a sight is quite common in Gibraltar and at the Bosporus,
afaik.
BTW,
are there storks in the Americas?
Georg
August 31st, 2010 at 10:06 am
Oh the glories of astronomy! 1.74 solar-mass 465.14 Hz pulsar PSR J1903+0327 is in a 95.17-day 0.437-eccentricity orbit with its 1.05 solar-mass star companion: 27% vs. 1.4·10^(-4)% gravitational binding energy, 1.8·10^11 vs. ~30 surface gees, 2·10^8 gauss vs. ~5 gauss magnetic field; superconductive compressed neutrons plus conjectured core compositions including hyperons, delta isobars, deconfined quark matter, Bose condensate, meson condensate (pion, kaon)… vs. proton-electron plasma; pulsar equatorial spin more than 11% lightspeed. Despite all that relativistic and quantum mechanical otherworldy goodness, the orbit, orbital precession, and orbital decay from gravitational radiation each and all validate General Relativity to the limits of observational error.
Nothing within physics’ imagination remains that can measurably violate the Equivalence Principle, the assumption that everything falls identically in vacuum (e.g., Einstein’s elevator). Chemistry imagines a very different kind of spinning firestorm: Enantiomorphic crystal structures are fundamentally helical in opposite senses. Do opposite shoes violate the Equivalence Principle?
http://www.mazepath.com/uncleal/erotor1.jpg
Somebody should look. The worst it can do is succeed.
August 31st, 2010 at 10:24 am
Uncle Al says: Nothing within physics’ imagination remains that can measurably violate the Equivalence Principle, the assumption that everything falls identically in vacuum (e.g., Einstein’s elevator).
I dunno: physics can imagine quite a lot.
Does the equivalence principle hold at microscopic/atomic scales? Something has to give between General Relativity and QCD, and this seems the most likely place.
It’s *really* hard to study strong gravitational gradients at the atomic scale.
August 31st, 2010 at 12:52 pm
Oh man. Way cool, but I’d have been holding up my soggy pants while yelling “run away” in a Monty Python voice. That’s poop-inducing scary. Not that it’s new for this blog.
August 31st, 2010 at 4:38 pm
Yeah, they’re called fire storms. Some gigantic one’s can cause sucking winds of 50 mph. If you’re nearby, there’s no getting out, even with a car. Happens a lot after firebombing and nuclear attacks when lots of combustible material is around.
Hope I never have to be near one.
August 31st, 2010 at 6:27 pm
[...] http://blogs.discovermagazine.com/badastronomy/2010/08/30/another-tornado-made-of-fire-waiting-now-f... This entry was posted on Wednesday, September 1st, 2010 at 12:27 am and is filed under Weather. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site. [...]
August 31st, 2010 at 7:35 pm
I would love to see a computer modeling of this phenomenon in a high quality world simulator. I want to see this fire tornado from the inside.
August 31st, 2010 at 10:50 pm
I’m skeptical of the angular momentum claim. The center spins faster because that’s where the updraft is strongest. The rotation of a figure skater is not powered – it exists before it gets focused into a spin. But the fire vortex is the result of energy being released at the center, not necessarily the contraction of an existing circulation. My understanding is that convective tornadoes will occasionally spin clockwise even though the larger system that generates them is always rotating counterclockwise (pardon my northern hemisphere bias).
I’m not an expert and maybe you’re right for reasons I don’t understand, but I think your analogy needs closer scrutiny.
August 31st, 2010 at 11:01 pm
@^ Joseph :
Not in person you don’t!
Great write-up as ususal and awesome videoclip there – thanks BA.
September 1st, 2010 at 2:40 am
Various names: fire whirl, fire devil (from dust devil), fire vortex.
You would see more images of them except that the people close to fires big enough to produce them have other things on their minds … they are usually fighting the fire or else running like hell for safety.
Some of the crews on the Rodeo-Chediski fire in Arizona reported seeing these. It was not a good sign, because it means the fire is making its own weather.
http://www.fs.fed.us/fire/fmt/fmt_pdfs/fmt63-3.pdf (page 56) reports on one that was big enough to break large trees.
September 1st, 2010 at 5:52 am
[...] video, and later got hold of another one filmed in Honolulu, which is even cooler, and which he posted along with a breathless explanation of how this phenomenon [...]
September 1st, 2010 at 9:08 am
That’s nothing.
September 1st, 2010 at 9:23 pm
@ ^ Lex : LOL.
Nice one. Fire hurricanes. There’s an Emmerich (Independence Day, Day After Tomorrow, 2012) movie in that.
September 2nd, 2010 at 12:40 am
[...] Another tornado MADE OF FIRE! Waiting now for tornado made of locusts. (blogs.discovermagazine.com) [...]
September 6th, 2010 at 1:57 am
Fire vortexes are actually really common, especially if the conditions are right. Back when I was a firefighter we could almost produce them at will.
A long, fuel-heavy fire-front (a long trough of flammable liquid used in training was best) would generate a few each time it was lit. 15-30cm wide, a few meters long, fill with petrol and light (for anyone wanting to test it out).
It was really starting to annoy me that every blog that posted the video ran with the headline that was used wherever they sourced it from – that the fire vortex is rare. “Hey, they said it was rare, so it must be, I’ll say it is rare too.” Not one site bothered to check.
September 13th, 2010 at 10:26 am
[...] a bit late to covering fire tornadoes – National Geographic, Boing Boing and the Bad Astronomy blog have all written about how they form and how to fight them during the last few weeks. But I [...]
November 4th, 2010 at 11:55 am
[...] “This really is a fantastic demonstration of how microscale weather works. Imagine: a fire starts. As the air is heated above the fire, it rises, and the upward motion can be very strong. This leaves a lower pressure spot at the fire, and the air from outside the fire rushes in to fill the gap. The air is very turbulent, and as the inward-moving air from one side hits air coming in from the other, swirls can form. These get amplified by the constant gale of air, and rotation on a larger scale can get started and sustained. The whirlwind gets pumped by the hot air rising, and the next thing you know you’ve got a full-blown tornado of fire.” – From Discover Magazine [...]