War would see an increase in bitcoins price but a natural disaster? I'm not sure. It depends how many places it affects since if it's just a small country or a few islands it wouldn't affect the price at all even if the people there had to spend all of their bitcoins.
Yes, also bitcoin is not affected by some disasters that has nothing to do with business or no money involve, Bitcoin depends on the number of users and supporters of the said currency, It i easy to say that bitcoin will be affected by calamities and other natural disasters which is not, Bitcoin can be affected by the decrease of people using it.