There wasn’t enough gasoline in south Florida to evacuate the population. Simple high school math gets us close to an answer why. We’ve taken efficiency to a new extreme, and made ourselves less secure. We pursued economic efficiency, and see where it’s left us?
The population of Florida is about 20 million people. Say you need to evacuate 8 million of them. They have to drive an average of 450 miles to safety. Figure three persons to a car at 25 miles per gallon. We’re going to need about 48 million gallons of fuel to get people out, and their car is empty when they arrive at their destination. Obviously, they will want to buy more gas as they go. There are about 5500 gas stations in Florida according to WolframAlpha. That means each gas station needs about 8800 gallons of storage per station to handle the exodus. My local station only carries 15 thousand gallons. Most of the time the stations have less on hand, so your mileage may vary. If everyone shows up to fill their tanks and leaves, then the stations run out of gas.
How many gas stations does your city need? It needs enough underground storage to drive every resident at least 100 miles. At this point, a smart government policy would be to stop taxing gas stations because we need more of them, not less.
There are small steps we can take until then. Preppers want to keep their gas tanks at least half full. Gas stations could do the same.