100-year flood

A flood event that has a 1% probability of occurring in any given year; an exceptionally large flood.

Japanese Meaning

百年に一度の洪水。1年あたり1%の確率で発生する、非常に大規模な洪水現象を指す。

The town's emergency plan was revised after engineers modeled the impact of a 100-year flood on the levee system.

技術者が年に1%の確率で発生する洪水が堤防に与える影響をモデル化した後、その町の緊急対応計画が改訂された。

Sense（1）

A flood event that has a 1% probability of occurring in any given year; an exceptionally large flood.

100-year floods

（ plural ）