火災 かさい積乱 せきらん くもではありませんでした
ka saiseki ran kumodewārimasendeshita

Noun
Desu Copula

The polite, past negative form of 火災積乱雲

1. It was not a firestorm.; It was not a cumulonimbus cloud caused by a fire.

Past/Perfective
Negative
Polite
Formal Register