Something that’s cataclysmic is violently destructive. The word often refers to natural disasters, like a cataclysmic earthquake, but cataclysmic can describe other events as well as long as they’re bad enough, like the cataclysmic failure you had making meatloaf.
Earthquakes, volcanic eruptions, floods, tornados, landslide . . . These natural disasters are often described as cataclysmic when they cause great devastation. Cataclysmic isn't just for describing natural disasters — personal disasters can be called cataclysmic as well if you want to emphasize just how badly something turned out. If your meatloaf is just so-so, it’s not so disastrous. But if it’s so spectacularly bad that no one can eat it? That’s a cataclysmic failure.