POMPANO BEACH, Fla. — Hurricane Irma swept across the Bahamas and Cuba on Friday and was expected to continue lashing them with rain Saturday as the deadly storm hurtled toward Florida’s doorstep and threatened to ravage the state with destruction not seen in a generation.

As the weather forecasts and warnings from officials grew increasingly dire, hundreds of thousands of people across Florida fled their homes in an effort to get out before the rapidly-closing window to escape Irma’s wrath slammed shut. Forecasters said Irma, a storm of remarkable size and power that has already battered islands across the Caribbean, would approach South Florida by Sunday morning and could slam ashore there before tracking up the state’s spine.

“It’s not a question of if Florida’s…