A power grid fails, which then stops water pumps, causing a water shortage. This shows how one problem can cause many others. What is this chain reaction called, and why is it tricky to find these weaknesses beforehand?

The chain reaction described, where the failure of one system triggers the failure of others, is called a cascading failure or a cascading effect. A cascading failure occurs when the failure of one component or system leads to the failure of successive components or systems, thereby propagating an initial localized problem into a widespread and often more severe system-wide collapse. This process highlights the concept of interdependencies, which are relationships where the operation and reliability of one critical infrastructure system, such as a water supply network, are reliant on the proper functioning of another, like the power grid.