Thread by @andyprata

Big eruption from Hunga Tonga-Hunga Ha'apai. Lots of ice. Some SO2. Ash difficult to detect with the usual methods. Cloud-top temperatures reaching 182 K (-91°C), likely stratospheric (>16.5 km asl). #HungaTongaHungaHaapai #HungaTonga

Incredible overshooting top at 05:50 UTC too (data courtesy JMA, processed with SatPy).

Here's a nearby sounding at 12:00 UTC on 13 Jan, which is around the time of the eruption (15:00 UTC on 13 Jan). Tropopause at ~16.5 km. Note all temperatures warmer than -85°C, which suggests undercooling of the plume.

Tropomi seeing SO2. Data recieved from the SACS alert system (sacs.aeronomie.be).

Lots of lightning. 86,000 lightning events detected so far:

Some photographs from Tonga Geological Services, Government of Tonga. Very similar to Anak Krakatau.

And video from sea level (with lightning!):

And incredible view from the #ISS:

Here's the latest eruption. Again ice detectable. This time ash signal appearing. Plume appears to be significantly stronger than the last one. I've set the colour bar and scale to try to highlight the tropospheric and stratospheric portions of the plume (top left plot).

There's some debate about the height of the plume. We know that if the plume entered the stratosphere it will be transported by the stratospheric easterlies. (1/3)

Tropopause is at ~16.5 km and easterlies are apparent from 16.5-30 km. (2/3)

For this scene, temperatures in the stratospheric portion of the plume are mostly ~230 K (-43°C), which corresponds heights of ~30 km (asl), assuming thermal equlibrium. Remember Pinatubo reached ~40 km asl. (3/3)

@BOM_au now issuing a tsunami warning near where I live(!). For official updates on this follow their account.

A great summary article from @scronin70 on Hunga Tonga-Hunga Ha'apai: theconversation.com/why-the-volcan…