It’s the stuff of Floridians’ nightmares: a hurricane that blows up to unprecedented Category 6 strength just before it slams into Miami and renders the southern part of the state uninhabitable.

Bruce Holsinger’s new novel, “The Displacements,” begins in the not-too-distant future with just such a storm, Hurricane Luna.

Luna’s rapid intensification, the product of climate change, brings a surge that inundates Biscayne Bay and everything around it, 215-mph winds and, within the first two hours, 22 inches of rain. Miami Beach and much of Miami are simply gone.

The evacuation order is massive and last minute. Stuck in the middle are Daphne Larsen-hall, her two young children, her 19-year-old stepson and the family dog.

When the order comes, Brantley, a surgeon, rushes off to the hospital where he works to help evacuate patients, telling Daphne and the kids he’ll meet up with them. The family van runs out of gas before they get to Gainesville, and Daphne discovers her purse is missing. No cash, no credit cards, no phone.

The family joins a crowd trekking toward a reception center that’s processing hurricane refugees. They’re put on a bus for one of the Federal Emergency Management Agency megashelters around the country, this one in Oklahoma. The woman in charge of managing its 10,000 inhabitants is Rain Holton, a disaster assistance engineer for FEMA.

Where there are vulnerable people, there are predators. Back in Houston, Tate Bondurant was an insurance agent with a sideline in selling opioids. Before Luna hit, his mule, a musician named Jessamyn, delivered a new drug called wildfire, “with ten times the potency of oxycontin.”

Tate figures his Russian suppliers won’t find him in the shelter under a fake name, and he can sell the drugs and keep the payoff.

Daphne’s family will be affected by Tate and Jessamyn in unexpected ways. And much will be revealed about the missing Brantley.

DETAILS

“The Displacements” by Bruce Holsinger; Riverhead Books (448 pages, $27)