Kilauea, continuing to showcase its eruptive wares to the watching world, isn’t just content with producing blue fire. As reported by the United States Geological Survey (USGS), it’s also creating its own damn weather systems. Specifically, it’s producing “pyrocumulus” clouds, the volcanic equivalent to cumulus clouds – which can cause thunderstorms.
Sometimes known as flammagenitus clouds or simply “fire clouds”, these are formed when intense heating of the ground triggers the formation of large convection cells, where warm air rises, normally imbuing itself with moisture as it goes. When it reaches a point of stability in the atmosphere – when the air mass is as dense as the air surrounding it – it stops moving.
The cooler air around it then condenses out, and these impressive clouds form. Any meteorology fans out there may have clocked that this is essentially what you need to fuel a thunderstorm: moisture, a buoyant lifting force (the heated surface), and a mass of unstable air.
The USGS explains that they pose the same hazards as a thunderstorm. “They don’t hold volcanic ash, so they don’t have any additional hazard from electrostatically charged ash particles.” Indeed, they’re not to be confused with ash columns erupting from (normally) explosive eruptions, which can, under certain conditions, create volcanic lightning and thunder – the latter of which was just recently recorded for the very first time.
Funnily enough, pyrocumulus cloud formation isn’t normally associated with this type of volcanic eruption. It's normally associated with paroxysmal, explosive volcanic eruptions or enormous forest fires.
Back in 2014, for example, California was experiencing a somewhat exceptional drought. Vegetation became far drier than normal, and in August of that year, huge forest fires were ignited, with more than 400 square kilometers (150 square miles) turned into a conflagration in a matter of a few days. This intense supply of heat, as it so happens, created pyrocumulus clouds that could be seen from space.
In the case of Kilauea, however, it appears that the hardworking Fissure 8 – one of the most active, by far, in the lower East Rift Zone (LERZ) – is seemingly supplying so much thermal energy to the ground there that it’s enough to cause a giant mass of warm air to elevate.