@Lorraine115
I would message your upcoming guests and advise them of your situation as they may need to know sooner rather than say at the last minute as to whether they will have accommodation...indeed if you dont have power..i would guess others in the area do not either.
I would send a message to Airbnb and explain (see link below) if indeed you are going to cancel ...list the reservations and maybe include some evidence about the power problem...
eg, news articles..photos....something to back up your claim of "extenuating circumstances "
https://www.airbnb.com/help/article/1320/what-if-i-need-to-cancel-because-of-an-emergency-or-unavoid...