This was a Blackswan event, by definition unpredictable. Sure, some people raised it before the event, but so have been major earth quakes, tsunami's, literally events out of the bible.

I think a better thought is how to become Anti-fragile (checkout the book by Nicholas Taleb)

Climate change. It's already been extensively written about, it's already happening, and we are certainly doing too little.

The next Star Wars movie will probably be as big a disaster as the last one.

A major west coast earthquake, probably.

Two, cascadian subduction zone or California.