Volcanic tornadoes

[Juliett Bravo Kilo]

Not sure where else to post this, but given that pyrotornadoes (tornadoes spawned from pyrocumulonimbus clouds) are a recognized phenomena now, I figured this might be of interest. A series of vortexes/whirlwinds spawned in the aftermath of a pyroclastic flow from a volcanic eruption.



Not sure what you'd call these, pyrotornadoes, ashnadoes, ash devils?

There are so many vortexes recognized in nature now, how could they all be classified neatly. I've seen the following labels: Dust devils, steam devils, snow devils, debris devils, leaf devils or hay devils, water devils, coal devils, ash devils, what's next?

 

[MNTornadoGuy]

Not sure where else to post this, but given that pyrotornadoes (tornadoes spawned from pyrocumulonimbus clouds) are a recognized phenomena now, I figured this might be of interest. A series of vortexes/whirlwinds spawned in the aftermath of a pyroclastic flow from a volcanic eruption.



Not sure what you'd call these, pyrotornadoes, ashnadoes, ash devils?

There are so many vortexes recognized in nature now, how could they all be classified neatly. I've seen the following labels: Dust devils, steam devils, snow devils, debris devils, leaf devils or hay devils, water devils, coal devils, ash devils, what's next?

Interestingly during the 1815 eruption of Tambora, a gigantic whirlwind struck a village over 25 miles from the volcano's summit. The whirlwind lifted up trees, homes, and people. More recently during the 2014 Holuhraun eruption, at least 21 pyrocumulus-related landspout tornadoes occurred over multiple days.

 

[TH2002]

Although there hasn't been much research on volcanic tornadoes until recently, I do think they are a MUCH more frequent phenomenon than many are led to believe. They probably have much in common with landspout tornadoes in that the spinning motion likely originates near the ground and the rotating column of air is ingested into a pyrocumulonimbus cloud, though they may also have more in common with dust/steam devils.

Some videos of volcanic tornadoes on Hawaii's Kilauea volcano:

 

[MNTornadoGuy]

Although there hasn't been much research on volcanic tornadoes until recently, I do think they are a MUCH more frequent phenomenon than many are led to believe. They probably have much in common with landspout tornadoes in that the spinning motion likely originates near the ground and the rotating column of air is ingested into a pyrocumulonimbus cloud, though they may also have more in common with dust/steam devils.

Some videos of volcanic tornadoes on Hawaii's Kilauea volcano:

Besides the 1815 Tambora event, I don't think there have been any significant volcanic tornadoes recorded in recent history. They seem to be mostly pretty weak.

 

[TH2002]

Besides the 1815 Tambora event, I don't think there have been any significant volcanic tornadoes recorded in recent history. They seem to be mostly pretty weak.

Makes total sense, especially if the way they form has a lot in common with dust/steam devils. There are a few cases of wildfires spawning EF3 tornadoes (Mt. Arawang, Australia from the Canberra bushfires in 2003 and Redding, California from the Carr Fire in 2018) - I'd imagine the conditions under which they form would be very similar to volcanic tornadoes, however as you said besides the Mt. Tambora event we haven't actually documented an intense one yet.

 

[bjdeming]

These exist and are fascinating. Hope it's okay to play devil's advocate on the 1815 "whirlwind."

That's how the Rajah of Sanggar described the destruction of his realm, but there was no other word for such phenomena back then. (Thirty thousand people died on Martinique in 1902 before Alfred Lecroix recognized these long-distance volcanic killers: nuees ardentes, he called pyroclastic flows, which travel almost friction-free on hot gases. They can cause tornado-like destruction and trauma with their high-speed winds and debris, in addition to all the heat- and gas-related deadliness. Weird things happen in these clouds: on Martinique, for example, after the first surge went through the city of St. Pierre, two people were found sitting at their breakfast table, dressed, unburnt, and dead. Elsewhere in the ruined town there were unbroken glasses found next to twisted, seared metal -- that sort of tornado-like effect, but not from an event that was primarily a vortex. Am getting this info on effects from the Zebrowski reference at the above link, by the way.)

Maybe pyroclastic flows -- the big ones, anyway -- contain some vortices? Wish THAT could be filmed safely.

At Tambora in 1815, there was a lot more going on with the volcano at that point, which isn't the case with the videos above, even the first one, which is at Sinabung, on northern Sumatra, where I think vortices were first filmed. It's an explosive volcano, but usually does exactly what it's doing in that video (and right now, too): oozing out sticky lava at the summit. Parts of the dome frequently collapse, causing a pyroclastic flow.

Those vortices formed on the hot flow field. The ones at Kilauea formed above a lava lake that had fountaining going on. So, in each case, there's a hot basal surface and -- just thinking on my feet here -- also there's movement of solid material through the air that may help trigger column rotation.

At Tambora in 1815, on the other hand, the unfortunate rajah was watching the climactic phase of a VEI 7 eruption. Per this source the whirlwind sounds more like what they now call a pyroclastic surge, which happens as the gassy force propelling the eruptive column upwards loses pressure.

They just didn't have terms for such an extreme event back then, though they did have cyclones and tornadoes (Indonesia gets tornadoes, right?).

FWIW, Clive Oppenheimer describes the 1815 whirlwind as pyroclastic flow in his book on eruptions that "shook the world."

Other historic reports might be worth checking, though, particularly Vesuvius. It has had many violent eruptions (not just Pompeii), and there were several scientific observers around for the show in 1906 and afterwards.

 

[MNTornadoGuy]

These exist and are fascinating. Hope it's okay to play devil's advocate on the 1815 "whirlwind."

That's how the Rajah of Sanggar described the destruction of his realm, but there was no other word for such phenomena back then. (Thirty thousand people died on Martinique in 1902 before Alfred Lecroix recognized these long-distance volcanic killers: nuees ardentes, he called pyroclastic flows, which travel almost friction-free on hot gases. They can cause tornado-like destruction and trauma with their high-speed winds and debris, in addition to all the heat- and gas-related deadliness. Weird things happen in these clouds: on Martinique, for example, after the first surge went through the city of St. Pierre, two people were found sitting at their breakfast table, dressed, unburnt, and dead. Elsewhere in the ruined town there were unbroken glasses found next to twisted, seared metal -- that sort of tornado-like effect, but not from an event that was primarily a vortex. Am getting this info on effects from the Zebrowski reference at the above link, by the way.)

Maybe pyroclastic flows -- the big ones, anyway -- contain some vortices? Wish THAT could be filmed safely.

At Tambora in 1815, there was a lot more going on with the volcano at that point, which isn't the case with the videos above, even the first one, which is at Sinabung, on northern Sumatra, where I think vortices were first filmed. It's an explosive volcano, but usually does exactly what it's doing in that video (and right now, too): oozing out sticky lava at the summit. Parts of the dome frequently collapse, causing a pyroclastic flow.

Those vortices formed on the hot flow field. The ones at Kilauea formed above a lava lake that had fountaining going on. So, in each case, there's a hot basal surface and -- just thinking on my feet here -- also there's movement of solid material through the air that may help trigger column rotation.

At Tambora in 1815, on the other hand, the unfortunate rajah was watching the climactic phase of a VEI 7 eruption. Per this source the whirlwind sounds more like what they now call a pyroclastic surge, which happens as the gassy force propelling the eruptive column upwards loses pressure.

They just didn't have terms for such an extreme event back then, though they did have cyclones and tornadoes (Indonesia gets tornadoes, right?).

FWIW, Clive Oppenheimer describes the 1815 whirlwind as pyroclastic flow in his book on eruptions that "shook the world."

Other historic reports might be worth checking, though, particularly Vesuvius. It has had many violent eruptions (not just Pompeii), and there were several scientific observers around for the show in 1906 and afterwards.

It is quite possible that they were simply describing pyroclastic surges or flows. Anyways it seems that volcanic tornadoes are usually far weaker than tornadoes generated by a wildfire pyrocumulonimbus.

 

[Juliett Bravo Kilo]

It is quite possible that they were simply describing pyroclastic surges or flows. Anyways it seems that volcanic tornadoes are usually far weaker than tornadoes generated by a wildfire pyrocumulonimbus.

Probably because they're not true tornadoes, just vortexes. That said, in massive eruptions (like Tambora, Pinatubo, Krakatoa) pyrocumolonimubus clouds can be generated, so it's possible true tornadoes have been spawned from those, not sure if it's been reliably documented though. And yeah, the 'whirlwind' from Tambora is most likely a pyroclastic flow.

 

[bjdeming]

This diagram is interesting, though it's almost 11 years old.



Credit: Zina Deretsky, National Science Foundation, after Chakraborty et al., Volcanic mesocyclones, Nature, 3/26/09

from

Tornado-like Rotation Is Key to Understanding Volcanic Plumes

Sea captain's historic report, modern photographs, lead scientists to new conclusions

www.nsf.gov

I think the eruption in the graphic is Mount St. Helens, 1980 (VEI 5).

Here's some images of that impressive Pinatubo cloud (along with the typhoon). Seeing it called a mesocyclone: wow! But then, just seeing it is gobsmacking. (VEI 6: Tambora's eruption was about 10x bigger.)


And back when lava ran into the sea at Kilauea, there were those cute, human-friendly vortices over water: https://www.diyphotography.net/bruce-omori-describes-like-photograph-7-volcanic-vortexes/

 

[MNTornadoGuy]

This diagram is interesting, though it's almost 11 years old.

View attachment 5813

Credit: Zina Deretsky, National Science Foundation, after Chakraborty et al., Volcanic mesocyclones, Nature, 3/26/09

from

Tornado-like Rotation Is Key to Understanding Volcanic Plumes

Sea captain's historic report, modern photographs, lead scientists to new conclusions

www.nsf.gov

I think the eruption in the graphic is Mount St. Helens, 1980 (VEI 5).

Here's some images of that impressive Pinatubo cloud (along with the typhoon). Seeing it called a mesocyclone: wow! But then, just seeing it is gobsmacking. (VEI 6: Tambora's eruption was about 10x bigger.)


And back when lava ran into the sea at Kilauea, there were those cute, human-friendly vortices over water: https://www.diyphotography.net/bruce-omori-describes-like-photograph-7-volcanic-vortexes/

That study of volcanic mesocyclones is controversial and has been disproven by another study.

 

[bjdeming]

That study of volcanic mesocyclones is controversial and has been disproven by another study.

Reference(s)? I'm thinking of doing a post on this now.

 

[MNTornadoGuy]

Reference(s)? I'm thinking of doing a post on this now.

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agupubs.onlinelibrary.wiley.com

 

[bjdeming]

Vortex spotted on thermal cam yesterday at Mount Etna, which is VERY active right now:

 

[Juliett Bravo Kilo]

Not sure where else to put but another interesting example of Mother Nature's vortexes....perhaps this could be called a "water devil"? Don't really think it warrants the label of "waterspout".

 

[MNTornadoGuy]

Not sure where else to put but another interesting example of Mother Nature's vortexes....perhaps this could be called a "water devil"? Don't really think it warrants the label of "waterspout".

That's a mechanical vortex generated by airflow up the cliff.

 

[Juliett Bravo Kilo]

Given that it involved Yellowstone and is a vortex, I figure I might as well post this article about a steam devil spotted over Yellowstone Lake 7 years ago. It apparently lasted for over 15 minutes, quite a long time for a steam devil and was unusually large in diameter (for a steam devil).

| EarthSky

Steam devils are rare, but they may form over large lakes and oceans during cold weather, if the water below is still relatively warm. See it on EarthSky.

earthsky.org

And now I just will post a couple other steam devil videos as I find them quite entrancing and ethereal to watch, especially in person:

1.

2.

3.

4.

 

[MNTornadoGuy]

Given that it involved Yellowstone and is a vortex, I figure I might as well post this article about a steam devil spotted over Yellowstone Lake 7 years ago. It apparently lasted for over 15 minutes, quite a long time for a steam devil and was unusually large in diameter (for a steam devil).

| EarthSky

Steam devils are rare, but they may form over large lakes and oceans during cold weather, if the water below is still relatively warm. See it on EarthSky.

earthsky.org

And now I just will post a couple other steam devil videos as I find them quite entrancing and ethereal to watch, especially in person:

1.

2.

3.

4.

That steam devil over Yellowstone Lake looks like a winter waterspout as it is connected to the cloud base.

 

[Juliett Bravo Kilo]

That steam devil over Yellowstone Lake looks like a winter waterspout as it is connected to the cloud base.

So would that be called a snowspout? Or not? Seems like a pretty rare phenomena then that got misidentified. Interesting.

 

[MNTornadoGuy]

So would that be called a snowspout? Or not? Seems like a pretty rare phenomena then that got misidentified. Interesting.

Yes they are also known as snowspouts.

 

[MNTornadoGuy]

Now even though these definitely are not true tornadoes by any means, a very interesting type of volcanic vortex is pyroclastic surge vortices. These have been only studied once, during the 1951 Mt Lamington eruption. They seem to be generated by extreme turbulence within the surge and travel outwards creating streaks of intense damage. These vortices were likely responsible for unusually intense damage within a village downstream of the volcano. Here buildings were completely swept away with debris being scattered for a wide area, a steel-framed hospital was leveled and a car was lofted into the top of a tree.