the.com/perfect storm

means A rare, disastrous convergence of several bad factors at once, each one survivable alone but catastrophic together.

from Popularized by Sebastian Junger's 1997 book 'The Perfect Storm,' about a 1991 fishing boat lost when a hurricane, a cold front, and a nor'easter collided off the Atlantic coast — three separate storm systems merging into one monster. The phrase existed in meteorology before that, describing the rare pile-up of ideal conditions for maximum destruction, but the book and its 2000 film adaptation are what pushed it into everyday use for any situation where everything goes wrong at once.