Volcanic tornadoes (2 Viewers)

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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.


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I think something similar to this happened in the 1815 Tambora eruption.
 
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I should've put more in my reply, this comment of yours was what I was thinking of:



Yeah it's hard to know for sure what happen but I think stuff like this is more common than previously thought (like pyrotornadoes).
 

MNTornadoGuy

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I should've put more in my reply, this comment of yours was what I was thinking of:



Yeah it's hard to know for sure what happen but I think stuff like this is more common than previously thought (like pyrotornadoes).
It probably is common in large pyroclastic surges but since damage surveys of surges are rare, they are not well-documented at all.
 

bjdeming

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This isn't one of the biggies, and in fact, the phenomenon has been observed when Kilauea's lava was entering the sea (and probably elsewhere at various volcanoes), but it's cool that pioneering volcanologist Frank Perret snapped a shot (with his trusty folding 3A or 2C Kodak pocket camera) of what he called a "spiracle" during Sakurajima's big 1914 eruption in Japan that joined the island volcano out in Kagoshima Bay to land.

As he was an electrical engineer at heart, in addition to knowing physics, his caption links the vortice to clouds above through electricity, though I don't know how well that idea has held up over time. He, and some other scientific and soldierly lunatics did walk twice through an eruption plume at Vesuvius that was electrically charged and drawn to the ground (the guy had worked with Edison, as well as inventing various types of electrical machinery and a few electric cars, so I trust his description of that very dangerous hike, though I haven't come across anything recent about this -- just some things about volcanic lightning).

He also describes second-hand reports of vortices at Vesuvius in 1906 (that was a really big eruption, too). These were on land, on very hot debris avalanche fields, not associated with the "electric plume."
 
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MNTornadoGuy

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540
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Apple Valley, MN
This isn't one of the biggies, and in fact, the phenomenon has been observed when Kilauea's lava was entering the sea (and probably elsewhere at various volcanoes), but it's cool that pioneering volcanologist Frank Perret snapped a shot (with his trusty folding 3A or 2C Kodak pocket camera) of what he called a "spiracle" during Sakurajima's big 1914 eruption in Japan that joined the island volcano out in Kagoshima Bay to land.

As he was an electrical engineer at heart, in addition to knowing physics, his caption links the vortice to clouds above through electricity, though I don't know how well that idea has held up over time. He, and some other scientific and soldierly lunatics did walk twice through an eruption plume at Vesuvius that was electrically charged and drawn to the ground (the guy had worked with Edison, as well as inventing various types of electrical machinery and a few electric cars, so I trust his description of that very dangerous hike, though I haven't come across anything recent about this -- just some things about volcanic lightning).

He also describes second-hand reports of vortices at Vesuvius in 1906 (that was a really big eruption, too). These were on land, on very hot debris avalanche fields, not associated with the "electric plume."
Electricity was commonly said to be essential with the formation of tornadoes/atmospheric vortices back then but that has been proven wrong.
 

bjdeming

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An eyewitness report of vortices over flowing lava in Iceland and their observed cause -- hope they dig out the pix. This one was seen at the ongoing eruption at Fagradalsfjall last week at a time when the lava was very "gassy" (fountaining, lots of bubbles, and high SO2 output):


There's better video of one here (article is in Icelandic, but the video is stunning).
 

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