upheaval

An upheaval is a big change or disruption that affects many people or things.

When something big and unexpected happens, it can cause an upheaval. For example, if there's a natural disaster like a hurricane, it might cause an upheaval for people living in the affected area. They have to leave their homes, deal with damage, and adjust to a new way of life. Other times, upheavals come from human actions - like when a company suddenly lays off many employees or when there's a major change in government policies that affects everyone. In any case, an upheaval is something big and difficult to handle.