One way to hold this word: a fire so hot that it changes the air around it. The heat rushes up, air is dragged in from every side to fill the gap, and that inrushing wind makes the fire burn harder — which drags in more air still. The thing has stopped needing anyone to feed it. That closed circle is what firestorm carries, and it is the reason the word travels so easily from a burning valley to a page full of furious replies.
From the word’s history
The packet's source entry gives the word simply as fire plus storm. The two parts say the whole thing: a fire that has become a storm, and a storm that is made of the fire's own heat.
來源資料把這個字直接拆成 fire 加 storm。兩個部分就把整件事講完了：一場變成風暴的火，而那場風暴又是這場火自己的熱造出來的。
Wiktionary entry for firestorm supplied in evidence packet (kaikki:3f6f69a190036ae4:1222142186), From fire + storm
登入就可以看每一支怎麼連回核心畫面。