I am the host of a property in Puerto Rico! We have someone that arrives this Thursday August 29 - 31.
We are worried about the tropical storm watch due the tropical storm Dorian that is suppose to arrived between Wednesday and Thursday entering Cabo Rojo where our property is located.
You could contact Airbnb and maybe they cancel the reservation penalty free because of "extenuating circumstances". Otherwise the guest maybe want to cancel the reservation and claim afterwards a full refund for same reason:
hm, maybe it would be a good idea to cancel due to extenuating circumstances as @Emiel1 said because it could happen that your guest arrives, stay the whole duration of his booking and then gives you a low rating and ask for a refund afterwards because there was no electricity, wifi or your garden was muddy