氷河 ひょうが 決壊 けっかい洪水 こうずいじゃなかったです
hyōga kokekkaikōzuijanakattadesu

Noun
Desu Copula

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

1. glacial lake outburst flood wasn't.

Past/Perfective
Negative
Polite
Casual Register