MIAMI — Survivors of Hurricane Andrew — a Category 5 storm that decimated cities south of Miami — talk of pre-Andrew and post-Andrew as a kind of biblical milestone.

But out of the ruin of the 1992 storm came changes that helped remake the way South Florida, the state and the rest of the country confront hurricanes.

“Andrew kicked our butts and we learned from it — basically in South Florida, people were running around like crazy, mostly in circles,” said Richard Olson, the director of the international hurricane research center at Florida International University. “It was a marker event in the history of South Florida and for Florida in general. Nothing was ever the same in terms of mitigation and preparedness.”

As Hurricane Irma trounced several Caribbean islands and headed for Puerto Rico on Wednesday, South Florida prepared for the possible landfall this weekend of a Category 5 storm with 185 mile-an-hour winds. State officials rolled out carefully detailed protocols for evacuations, storm surges, emergency response and power losses.

Gov. Rick Scott did not mince words: “This is a devastating hurricane,” adding that “the storm is bigger, stronger, faster than Hurricane Andrew.”

Andrew, which blew in 25 years ago, was the last Category 5 storm to hit the United States, and it clobbered south Miami-Dade County, flattening houses and buildings.

After the storm, South Florida approved a building code intended to make structures better withstand high winds. The state came to be seen as an international leader in storm preparation.

Laws were passed that required supermarkets, gas stations and hospitals to be equipped with generators so they could reopen quickly after a storm. Residents took outfitting their homes much more seriously. In addition to hurricane-impact windows, which are now common, many South Floridians bought hurricane shutters. Some have installed hurricane resistant roofs.

The storm also gave rise to the modern-day federal, state and local emergency response system.

Counties invested in rescue boats and vehicles, and began training teams of emergency workers in how to deal with big storms. Miami-Dade’s swift-response teams are part of a small, specially designated federal network. One of the teams, along with other Florida emergency medical workers, went to Houston after Harvey.

“Andrew kick-started the professionalization of emergency management in Florida and, really, elsewhere,” Mr. Olson said.

But emergency managers are the first to say that hurricanes are unpredictable and foolproof plans are fiction. Hurricane Irma is anticipated to be a wind and storm surge rather than a rainstorm, which plays to South Florida’s strengths, forecasters said. A sudden change — like Houston’s 50 inches in rain — can upend the playbook.

“You have plans in place; you do drills, you make your notifications,” said Pete Gomez, the city of Miami’s emergency manager. “Sometimes you can prepare for everything, and something else hits you.”

Mitch Landrieu, the mayor of New Orleans and the president of the United States Conference of Mayors, warned that “even the cities that are the most forward leaning, if overtaken by a massive event like a Category 5 hurricane with 185 m.p.h. winds, will likely suffered significant damage.”

“There are some things that will just not allow you to defeat Mother Nature,” he said.

Gerald Galloway, a specialist on flood risk and floodplain management at the University of Maryland, agreed. While lauding Miami’s attention to windstorm preparedness, he said that its residents are “probably more sensitive to what would happen than what we saw in Houston.”

A punishing surge could do tremendous damage, despite the attention to wind standards in construction. Another potential question, Mr. Galloway said, is how effectively the standards are put into place. “They are certainly more attentive to it — but are they enforcing it? I’m not sure.”

“Whether it will make much of a difference with Irma,” he said, “will all depend on what the nature of the event is, and where it is.”