In this post from 2015, I discussed backing up your digital files. Whenever someone offers me actual physical documents related to my genealogy, I typically reply that I'd like to scan in the documents and give them back to the original owner. I'd prefer to NOT hold on to physical documents. Why? Because I can back up digital files so I should NEVER lose all of my data. That happened to me once about a year after I got my first modern computer. Yes, I lost data but really, it was nothing important. Now, if I lost all of my data, I would lose most of my years of genealogy work. That's why I'm so adamant about having at least two copies of my data in two different physical locations. Why two locations? Because no matter how careful you are, disaster can happen. Your home could flood, catch fire or get hit by a tornado or hurricane, or earthquake, or whatever natural disaster can occur where you are located. That's the same reason I don't like holding on to original documents. If disaster hits, you don't have two of those original documents.
However, if the choice is to keep original documents or throw them out, of course you're going to hold onto them. So, you have some important original documents related to your genealogy, or a historically important, unique, or expensive book that is not digitized, and you're in the path of a hurricane, as is currently bearing down on the east coast. What do you do to keep them from being destroyed if your home floods? Here are things I would consider.
First, one thing I own is a good quality vacuum sealer. I'd seal a book or a stack of documents in a bag, but instead of vacuuming all of the air out, I'd be sure to keep a good amount of air in the bag. This way if they end up fully in water, they could float. Then, once they're sealed in with an air pocket, I'd seal it in a second layer of vacuum sealed bag. This one I'd vacuum out the extra air. Then I'd put all of them into one or more plastic garbage bags and seal that to the best of my ability by tying it in a knot. Have some extra plastic totes? Put the garbage bags into those. With this many water-tight layers, I'd be pretty confident the books and documents wouldn't be destroyed by water.
All that being said, I would not keep these items in vacuum bags or any other plastic container. Chemicals can leach out of them and damage them. Keep them in archival-safe storage for the long term. Sealing against water is just for short-term insurance to keep them safe from an incoming disaster.
What about fires? What about tornadoes? There's only so much you can do to protect unique items from damage from fire or tornadoes. Your best bet to keep these safe is to take them with you. Maybe get a water-proof but relatively lightweight carrying cases and, when you hear about a fire or tornado that could destroy them, bring them to your vehicle and evacuate. Another good option, although it would be significantly more expensive is to get a large fireproof safe. Be sure the safe would protect paper contents from the high temperatures associated with fire.
Those of you on the east coast with the hurricane currently heading your way, start protecting your original documents now. If you're not currently in harm's way, come up with a plan and get the required equipment and supplies to use in the event of disaster. Whatever you do, no matter how important you believe your documents or photos are, they're not as important as your life. Stay safe!