My in laws are in North Miami. Our plan is for them to shelter in place. They don't get out much any way. They're in an apt building that's not in a flood zone. If the electricity shuts off they'll be without A/C and cooking (electric stove). But they have supplies - we hope enough for the duration.
My daughter and family are in South Florida, too. She's also in a building, and not in a flood zone. Her windows have hurricane glass. There's so much hype, and some Floridians say she's being naive in her preparations, although others were more reassuring. She's staying and has had trouble getting water bottles. She picked up extra canned food, but not enough to feed the family for a week. She's got flashlights and yortzeit candles and a radio that works on batteries, but can be wound up for power instead. I might suggest she pick up a new toy or 2 to better manage staying at home a few days. Although if the electricity goes out, things will get very difficult.
Even a day or 2 ago there was a lack of available flights out. And some scarcity of gas.