I was here for all 4 hurricanes last year - lost power for extended periods during 2 of them (7 days the 1st time & 5 the 2nd time). I carried a 6" fixed blade the whole time...
One thing I learned about having no power for days on end is that you always need a flashlight on you - even during the day. So I attached a small maglight sheath to my knife sheath & my little light rides 'piggyback' on my EDC knife.
Another thing I learned is that you will get very wet & dirty during the cleanup stage. So I think a kydex sheath might be a good idea.
So, my ideal 'hurricane knife' would include a kydex sheath with a pouch to hold a small flashlight. I'd say a leatherman tool too but the combined weight makes for an uncomfortable carry package unless you get a really small, light multi-tool...
That is a much nicer knife than the one I carried though!!!