onslaught

It simply wasn't prepared for a sudden onslaught of invasive species.

The cells that survive the impact, or are hurt or dying, scream in panic releasing an onslaught of chemical alarm signals that awaken your immune system.

Historians long pinned the start of the Viking Age to a brutal ambush on an English monastery in 793 CE, which the Anglo-Saxon Chronicle described as an onslaught of lightning, “fiery dragons,” and “heathen men.”