Our new @bullvolc paper is finally out on #VolcanicLightning during the submarine eruption of Bogoslof volcano in the Alaskan Aleutians! You can read the full study here--> rdcu.be/b1j0m. But here's what you need to know... [credit to @alaska_avo site for photos] (1/10)
From the surface, Bogoslof looks like any other wind-swept island, much beloved by seals, sea lions, and #puffins in the Bering Sea. It also happens to be an active volcano. The island is just the tip of the iceberg of a huge stratovolcano rising 6k ft from the ocean floor (2/10) 
Though Bogoslof had been asleep since 1992, it roared back awake in 2016, sending plumes of #VolcanicAsh & seawater as high as 12 km. Here's a rare view from Dutch Harbor. The aviation community was watching closely to reroute flight paths, but there was a problem... (3/10)
...monitoring these eruptions was not exactly straightforward. There were no sensors directly on the island and weird propagation effects in the seismic and infrasound data meant that #VolcanicLightning suddenly became useful for figuring out when there was hazardous #ash (4/10)
Wait a second. Volcanic lightning? Why?? That is literally what I ask myself eryday, and the reason for doing this study. Bogoslof had 70 explosions but only 32 created detectable lightning. Some of these plumes were monster lightning powerhouses; others were just duds. (5/10)
And this is where I'm going to tell you something sad. We don't have many pictures of the lightning. Here is The One photo, from a smartphone at night on a ship several km away (but seriously thank you @USCGAlaska). Not exactly #TaalEruption2020 but hey it is something (6/10)
Photographic analysis clearly wasn't going to do the trick during this eruption. We used global networks like @WWLLN @EarthNetworks & @VaisalaGroup to record lightning. We even installed some new sensors in the Aleutians to try to improve detection partway through eruption (7/10)
Now armed with some sweet data, it was time to crunch the numbers. Here's what I found. Bogoslof's plumes only created detectable lightning once they rose high enough to freeze. Yes, it gets cold in the upper atmosphere, and seawater carried by the plume turns to ice (8/10)
In essence, ice-charging electrified the volcanic plumes, just like in regular ole thunderstorms. Of course other collisions were going on (among ash particles). But those probably weren't generating enough charge to create powerful lightning. Ice was a major catalyst here (9/10)
The takeaway message is the that Bogoslof's #VolcanicLightning provided a reliable indicator of sustained, ash-rich plumes above the atmospheric freezing level. And that matters because it helps us estimate the height of hazardous #VolcanicAsh in near-real time (10/10)
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