JuliaJayne, I'm glad to hear that you and yours are all okay. These emergencies can really be hard on a person's nerves, even if no damage occurs to our loved ones or our property!
Gathering the vital records you list is a very good idea. Some people refer to this as their "red file." Whatever you call it, it's not only for emergencies such as golf-ball hail and tornadoes (or where I live in California, earthquakes and wild fires,) but to make it easier to manage vital records every time we visit a new doctor or register the kids for soccer. And it's necessary to be ready for the most common emergency we all face, no matter where we live: a house fire. (There was a great series of posts here on Unclutterer about a couple who lost it all in a Chicago house fire - search for it.)
The unfortunate truth is that there is no way to be prepared for an emergency that is absolutely guaranteed to be ideal in all situations. I may have my vital records ready to grab and go, but I may not be home when the emergency occurs. Still, it's advisable to have a grad-and-go solution in place.
A friend and colleague of mine recently received the sort of news we all dread: the local police in her town of San Bruno, CA, told her she needed to be ready to evacuate in 10 minutes due to a gas main explosion in her town. You may have read about it; several lives were lost, and many more homes. My friend had her vital records stored in my favorite tool - the Vital Records PortaVault (http://bit.ly/ViewPortaVault). With a suitcase, her computer, and spare meds plus the PortaVault by the door, (and her photos backed up online) she was ready to go when ordered. Happily, her house was spared. But she was ready to go without regrets.
Some answers to your questions: regarding an external hard drive, get one right away and back up your computer. It is the cheapest insurance you can get, not only in case of a weather emergency, but also for a hard drive crash (which is much more common than a damaging storm.)
And you'll also want to back up your computer offsite, so that (heaven forbid) if anything should happen to your house, you could still access your data. Services such as Mozy, Carbonite, and Crash Plan are ideal for this. At $50-100 per year, they provide a lot of peace of mind for a little cash. I actually use and external hard drive plus both Mozy AND Carbonite, which is like wearing a belt and suspenders and another belt. (Don't blame me if I look like a dork. I don't apologize for my "unfashionable" devotion to backing up :^)
Drop Box is another resource that can allow you to store vital information online in the cloud, so that if you should need to evacuate your home, you could still access vital records that you have placed in your DropBox. And it's free.
Make sure that you have digital records of cherished photos and essential records, plus any documents that are necessary to protect your business or your life functioning.
One way to get all your most important records scanned and stored digitally is to use a service like Scan Cafe, which scans a batch of photos and gives you a digital copy plus the originals. Or you can scan your own photos and vital documents. Two of the most popular tools are the Neat scanner (www.neatco.com) and a Fujitsu ScanSnap (http://scansnap.fujitsu.com/)
As AnotherDeb mentions, you'll want to think about where to keep your vital records so that the information is reasonably safe from prying eyes. You could keep your vital records binder in a safe, but that's slow and cumbersome if you need to evacuate quickly. Or you could keep it offsite, such as in a bank safe deposit box, but that's not fail-safe either. Some safe deposit boxes in New Orleans were inaccessible for two YEARS following Katrina, and safes in the World Trade Center were ineffective at guarding their valuables in the fire that began on 9/11. And if I needed to evacuate quickly in case of an earthquake, a safety deposit box in a bank closed for the weekend wouldn't be much help.
The best set of steps to take is:
1.create a grab-and-go file of vital records
2.scan documents that you would want to retrieve in an emergency - prescription information, insurance policies, identification, and so on.
3. keep your grab-and-go binder near the door in a nondescript-looking bag that you can easily carry (I use the PortaVault by securitaonline.com)
4. back up your computer to an external drive, in case of computer crash or theft
5. back up your documents offsite (using DropBox, Crash Plan, or similar), in case of evacuation.
Those 5 steps will take you a very long way to minimizing your loss and your regret in case of emergency, and they will enable you to rebuild your financial life as soon as possible.
Margaret Lukens, New Leaf + Company
(blogging on emergency preparation at http://www.preparation-nation.org)