My sister in Florida bought this in preparation for Irma. You can filter rainwater with it.

https://www.amazon.com/LifeStraw-Family-1-0-Water-Purifier/dp/B00FM9OBQS

Someone gave me one of these hand-crank lanterns as a gift. It doubles as a bright flashlight, so you may find it useful.

https://www.amazon.com/Rechargeable-Excellent-Outdoors-Emergency-Hurricane/dp/B00IDU65GM

There are also hand-crank or solar powered radios that double as flashlights and cellphone chargers.

https://www.amazon.com/Weather-WR182R-Radio-Flashlight-Dynamo/dp/B00B3B7E04