Onrush (noun)

1. A sudden and fast-moving flow or surge of people or things.
2. A swift and powerful forward movement or charge.
3. An overwhelming and sudden advance or attack.

Origin:

From the middle english 'on-rushen', which means 'to rush upon'.

Examples:

1. The onrush of water from the burst dam caused widespread damage to the nearby town.
2. The onrush of soldiers overwhelmed the enemy defenses, securing a decisive victory.
3. The onrush of shoppers during the holiday sales caused chaos in the stores.
4. The onrush of emotions was too much for her to handle, and she broke down in tears.
5. The onrush of adrenaline gave him the strength to lift the heavy object and save the day.