Kevin Langley took a key life lesson from Hurricane Katrina.

“Katrina didn’t cause the problems, it revealed the problems,” Langley said, referring to the societal and infrastructure challenges his hometown of New Orleans has long had. “It also revealed the opportunities; the opportunities to get things right.”

After the devastation of the monster storm that struck the Gulf Coast five years ago, Langley, 45, and other entrepreneurs in New Orleans stuck through the very hard times and came out stronger. As with many catastrophes, disaster can lead to more business for some. Others saw opportunities emerge as they launched new endeavors in the atmosphere the storm created.

New Orleans, Katrina’s Ground Zero, remains a changed city. Its population is 22 percent smaller than it was before the storm, one of the strongest hurricanes to slam into the region during a particularly angry 2005 season. Some businesses left completely, moving to nearby Jefferson Parrish, which has 8,222 more businesses now than it did the summer before the storm.

And even though Katrina spared some of the city’s most popular tourist areas, it damaged its well-known music scene: New Orleans has half the gigs for musicians it did before the storm, and they pay half as much, the Los Angeles Times reports.

Still, entrepreneurship has grown in the New Orleans area, with individuals starting businesses at a higher rate than nationally, with 450 per 100,000 people starting businesses, compared with 320 across the United States. And wages overall have grown 14 percent in the past five years, catching up to national averages for the first time since the 1980s, according to a Brookings Institution and Greater New Orleans Community Data Center report.

This summer, Portfolio.com spoke with a handful of interconnected entrepreneurs like Kevin Langley who survived Katrina and its aftermath and who stayed in New Orleans to rebuild their businesses and their lives.

No Option Except to Rebuild

In the late summer of 2005, Langley’s entire New Orleans neighborhood, most of the city he had called home for two decades, and his construction business were under water. His wife and 3-year-old triplets were living in Baton Rouge, sleeping in a room in his parents’ house that didn’t have power.

Looking out over his devastated Lakeview neighborhood, blocks from one of the city’s breached levies, Langley only had one choice as an entrepreneur. He had to persevere in the face of obstacles he’d never expected, and he had to keep the business he and partner Bret Ellis built, Ellis Construction, going.

“I had 45 employees, and each of those employees had four to five to six other dependents. Multiply that out and you have 400 to 500 people,” he said. “I took my business partner and we sat there and we said: ‘Look, we have to rebuild. There’s no decision, right?’”

Ellis Construction’s employees were scattered, some even living in cars in Wal-Mart parking lots. So Langley first had to round them up, reassure them, and put them back to work, even if it was only make-work while the partners figured out just what business they had left. Before the storm hit, the company had about 100 contracts lined up. Afterward, virtually none remained; with existing businesses destroyed, new construction was out.

It took two weeks for Langley and his partner to pull all their employees together. It took even longer for the floodwaters to recede. Ellis Construction started with makeshift offices in Baton Rouge before moving back to its digs in New Orleans once the ground finally dried.

Langley sat down with his employees and talked over the company’s situation. He and Ellis told them they would continue to be paid, but they didn’t know for how long. They had to cut manual checks because their payroll service had gone down. They set up trailers where 16 employees lived for nearly a year after the storm in the parking lot of Ellis Construction’s offices.

As for those offices, it took up to six months to get electricity. It took a year before regular phone service was restored. Langley rigged a point-to-point wireless connection from his office’s rooftop to downtown New Orleans and used Voice over Internet Protocol to communicate.

“It was a totally new environment, so we were a totally new company, even though we’re still the same name. We had to rethink everything,” he said. “We had to go to work and put our employees to work on whatever jobs were available.”

His is not the same company today as it was before Katrina. Despite work gained helping to rebuild New Orleans, many of the projects it lined up before the storm became tougher and more expensive to complete.

But that’s less important to him than what he’s been able to do as an entrepreneur in New Orleans. “I can tell you the punch line. The punch line is that entrepreneurs rebuild cities, and they provide quality of life and jobs for people,” Langley said.

A Mad Dash to Recover

Three weeks after the storm, in September 2005, Jude Olinger returned to his office in New Orleans from Baton Rouge. He already knew his office had been destroyed. It was housed in the same building as Ellis Construction, and Langley had told him of the flooding. Though the building stood, the first floor of the building was flooded to the desktop level. Olinger, “fighting the last war,” as he puts it, is now headquartered in a high-rise.

Stuck in Baton Rouge, Olinger scrambled to get his business, a market research firm called the Olinger Group, back up and running remotely. He raced around Louisiana’s capital city with two computer hard drives containing the data upon which his business depended, in search of someone with the skills to extract the information. “We were stuck in a city that had doubled in population and everyone was still shell-shocked,” Olinger, 43, said of Baton Rouge, 80 miles northwest of New Orleans.

He and his wife Erika—who had her own business back in New Orleans—worked 16- to 18-hour days knitting together the Olinger Group’s 10 employees. Because most of his clients, among them Fortune 500 companies, and vendors were from places other than New Orleans, his business could continue.

He still remembers the smell when he returned to his New Orleans office. It was an odor that permeated the city—stagnant water and mold. The office was a lost cause, with $225,000 worth of uninsured destruction. Files he had left behind that had once seemed crucial crumbled when he picked them up. Water still stood inside some computer monitors.

But his home and wife Erika’s art business were on high ground and were spared flood damage. “We had potable water and electricity, but that was about it” until the winter of 2005, Olinger said.

Five years later, Olinger sees where Katrina made him a more confident businessman, more focused on the most important aspects of work. “I now know that if we can survive that, we can survive anything,” Olinger said.