氷河ひょうが決壊けっかい洪水こうずいではありませんでした
hyōga kokekkaikōzuidewārimasendeshita

Noun
Desu Copula

The polite, past negative form of 氷河湖決壊洪水

1. It was not a glacial lake outburst flood.

Past/Perfective
Negative
Polite
Formal Register