The electric grid is pretty fragile...
No matter how solid the grid is, nothing is going to prevent you from losing power when a tree takes down power lines in your neighborhood.
I live in the Northeast where this is a normal occurrence. Power crews have it down to science, we usually get our power back in hours. Sometimes we get a very major storm event and we have to wait a few days because there are literally thousands of trees that have fallen across the region. But this does not mean the power grid is fragile. In fact, I'm always amazed at how quickly and efficiently the crews work to get everything back online.