"An incredible tornado of gas and fire, swirling 3,280ft (1km) into the air, has been captured on Wednesday last week above Iceland's rumbling Bardarbunga volcano, which has been exhibiting seismic activities and eruptions since last month with some of its lava fountain reaching as high as 700 feet in the air.
The footage was taken last week by an aircraft-fitted infrared camera designed to monitor and allow pilots to see potentially dangerous ash clouds.
Scientists are still unsure what caused the tornado-like phenomenon, but have suggested it may be due to the difference between hot and colder air rising above Bardarbunga (located under Vatnajökull, Iceland's most extensive glacier) has caused something similar to a 'dust devil'.
Dust devils are small, rotating columns of air, which can be seen because of the dust and debris they pick up from the ground. They form because hot air close to the ground rises, punching through the layer of cooler, denser air above."
http://austriantribune.com/informationen/144594-tornado-spotted-above-iceland-s-bardarbunga-volcano