Folks worry about zombies, asteroids or nuclear war as the agent of humanity's demise. It's the more mundane things, though, that should keep us up at night. To wit:
ARkStorm: California’s other "Big One"
While this is a hypothetical scenario, it still scares the crap out of me. Floods always have since childhood. I grew up in hurricane country. This is a tough balancing act, though, because you don't want to be too far from a water source.
This is also another reason to ensure you understand your local climate. Your life may depend on what you know might be possible.