Read on Twitter
"Contrary to a common misconception, the shape of the mushroom cloud does not depend on the nuclear or thermonuclear component; as you note, a massive detonation of chemical explosives would produce the same effect." https://www.scientificamerican.com/article/what-are-the-processes-th/
This happened in 2013, too https://www.popularmechanics.com/military/weapons/a8900/mushroom-cloud-physics-not-just-for-nukes-15363683/
here's a non-nuclear mushroom cloud from an explosion at a refinery in Pennsylvania in June 2019 https://www.nbc12.com/video/2019/06/21/explosion-pa-refinery-huge-mushroom-cloud/
Here's another angle on the 2013 one in Texas https://slate.com/technology/2013/04/is-this-texas-mushroom-cloud-photo-real-yes-but-it-s-from-2008.html
It doesn't have the same historical purchase, but to avoid confusion as to the nature of the explosion I'd have gone for the "a national disaster akin to the Halifax Explosion of 1917" https://maritimemuseum.novascotia.ca/what-see-do/halifax-explosion https://twitter.com/jenanmoussa/status/1290691749858422784
Here's the story this thread became https://www.forbes.com/sites/kelseyatherton/2020/08/04/think-halifax-not-hiroshima-for-beirut-explosion/#f0e01821c665
