Most low-probability, high-impact events are un-predictable by definition. Only in hindsight do they appear obvious. This has to do with many factors such as the narrative fallacy and confirmation bias, which Taleb describes as the Black Swan.

That being said, here a few high-impact (moderately low probability) events that could be on the horizon.

* Northern California Earthquake * Israel v Iran Nuclear Conflict that triggers WW3 * Singularity