score:3
If you ask to cancel your flight before the airline notifies you, then it will be considered a voluntary cancellation on your part and subject to the full penalties described in the fare rules.
Once the airline has notified you that the flight is not available and a new flight has been reserved for you, then you have a period of 24 to 48 hours to accept the new flight or request a refund.
In this particular case, due to the situation which is out of both parties hands (you & the airline), a caring airline would allow you to change or cancel without penalty, but they are under no obligation to do so.
I would call and ask, maybe you get lucky or maybe they re-iterate what I just wrote.