water bomb

American  

noun

1. a bag filled with water and mischievously dropped from a height upon a passerby below.

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Example Sentences

The five-day exercise simulates catastrophic floods from a "water bomb", an ever-present fear in a country where 60 percent of people live below sea level and climate change is making things worse.

From Barron's

He added that the dam was "going to cause an existential threat to our tribes and our livelihoods. It is quite serious because China could even use this as a sort of 'water bomb'".

From BBC

This is often called a "water bomb", where the upstream country can temporarily hold back water and then release it suddenly, without warning, causing massive damage downstream.

From BBC

“It wasn’t a water bomb, it was a tsunami,” Barbara Mayor Riccardo Pasqualini told Italian state radio, describing the sudden downpour Thursday evening that devastated his town in the Marche region near the Adriatic Sea.

From Seattle Times

Local authorities said they did not expect such a sudden “water bomb”, as around 400 millimetres of rain fell within two to three hours, inundating the streets of several towns in the Ancona and Pesaro-Urbino provinces.

From Reuters