Here in the Phoenix area we are at very low risk of a natural disaster/disaster. I think I looked it up once and the failing of our nuke plant an hour away was deemed the most probable (not very). Fire is something to consider, however.
We realized with Hurricane Sandy that we weren’t as prepared as we should have been. We had candles, flashlights, non-electric can openers, matches but we realized we did not have a battery operated radio and have since purchased one.
My meds would be the first thing I would take with me. I would prepare a backpack of couple changes of clothes, passport and other documents. We also keep a couple of hundreds around if needed. We moved our fire-proof safe, a small one to the upstairs double closet in younger d’s bedroom. When my daughters were little I always worried about losing pictures and so I routinely kept duplicate baby pictures and other photos in my Safe Deposit Box for years.
I would think in this disastrous situation in Houston there have to be people who are in shelters without their meds and children who might need epi-pens and inhalers.
Yes, I suspect there are quite a few folks without adequate supplies of medications in disasters, especially folks who can’t afford to get 90-day supplies of medications and have no idea what they will do when the current supply is exhausted.
I always feel most comfortable when I have an extra 30 day supply beyond whatever Rx I am taking. I generally travel with an extra 30 day supply as well. It just makes me more comfortable in case I misplace or end up using my Rx at a faster than planned rate.
Not having access to epi-pens and/or replacement inhalers for evacuees can be a huge issue very quickly.
The problem with medications is that the insurers will not allow you to refill your prescription until very close to the end of your 30 or 90 day supply. And in some cases, pharmacies will not refill it either even if you offer to pay full price. So in some situations folks could be stuck with just a few days’ supply.
I get all of my meds as soon as I can renew them and have slowly built up a fairly comfortable stash with most of them.
But my most important medicine gets delivered a few days before my infusion. I can’t stock that one ahead of time. 
It’s pretty common before a hurricane for insurance companies to allow filling a larger supply–usually 90 days.
That doesn’t help with disasters that don’t give warning. Which is one reason illl stay here and deal with hurricanes. 
I’ve built up a comfortable buffer with most of my Rx, since I’ve been on them for many years. I’d be very concerned about folks running out of Rx. It would be tough for them to each providers, pharmacies and even get their Rx when the city is in chaos.
“we realized we did not have a battery operated radio and have since purchased one.”
I’m thinking those crank type radios might be a good idea, too.
Direct Relief International is a great organization to look into if you want to give to a charity that specializes in medical relief.