Let me put it in a way you will understand.
If someone was coming to London from Glasgow and their 8pm train was cancelled, they would then have to catch one the next morning.
They send you a text at 9am, saying that their train was cancelled last night, so they will have to cancel their 2pm appointment with you.
You look on the live departures board at 9.05 am. The trains are running fine now. They must be lying!
You know a plane can't fly in a hurricane, right.
And even if it did not affect her specific town/island, it can't fly THROUGH a hurricane either.
So the airline has to cancel flights.
What do you think happened to all the passengers of the cancelled planes?
That they would sit on the laps of the passengers who were on pre booked flights?
The airline needs to RESCHEDULE thousands of people. It's not all going to happen in one day.