First of all, we need to understand the meaning of "black swan". Black swans are high impact, hard or impossible to predict events. So if we were to be able to predict them, they wouldn't be black swans!
So what is an IT professional to do? Act defensively. Let me give you an example.
You may or may not know about Black Monday, a day in 1987 when stock markets crashed around the world, precipitated by program trading. It began in Hong Kong, spread to Europe, and then the US.
At the time, my colleagues were working on a financial trading program for a clearing bank in Europe. Because it was clearing operation, the dollars traded were high -- minimum $10M per trade if I recall, with billions floating in the system at any time.
When the trading increased on Black Monday, the number of transactions went far above our normal, by 50%+. Black Swan event #1. This put an additional strain on the system. At the same time, a disk controller went bad and started "spraying" random zeros all over -- into file, into the disk catalog, the system sectors -- literally everywhere. Black Swan event #2.
So no problem everyone thought, we will use our disaster recovery tools to recover the application. But then, they all failed to work! Black Swan #3.
How could this be prevented and how would we defend against future triple black swans?
Well we started with a year long task force to review and repair as necessary all disaster recovery tools. Then we wrote a disaster recovery manual for application users, telling them what the tools were, what their responsibilities were, and what to expect from us.
Up until that point, we had been practicing whole system recovery drills on our data centers, and we started practicing on individual applications, with the cooperation of our clients.
So going forward, we felt well protected against black swans. No further black swans happened that I am aware of and the tools were reviewed regularly.