Soon after the Seacor Power departed from Port Fourchon on Tuesday afternoon, it found itself caught in a ferocious storm, facing up to 90 mph gusts and towering waves that capsized the commercial vessel carrying 19 people in the Gulf of Mexico.

One person was found dead on the surface of the water off Louisiana’s coast and a dozen passengers are still unaccounted for. Six were rescued and safely transported to shore.

The capsizing of the 129-foot liftboat sparked a massive rescue operation by the U.S. Coast Guard and a fleet of good Samaritans that continued on Wednesday. Less than a day after the vessel overturned, officials sought to maintain optimism that the missing could still be found.

“My heart and the collective heart of our team goes out to the families and to Seacor, but we’re giving it all we have,” Coast Guard Capt. Will Watson said at a news conference Wednesday.

Asked about the prospect of finding those still missing, Watson expressed hope.

“I’ll put it to you this way, whenever we engage, the Coast Guard engages in a search and rescue effort, we are hopeful,” he said. “You can’t do this work if you’re not optimistic, if you’re not hopeful when you do it. … We’re one day approximately into this operation and we’re giving it all we got.”

The Coast Guard received the initial alert from an emergency beacon at about 4:30 p.m. Tuesday, and the Coast Guard cutter USCGC Glenn Harris, a 154-foot rescue ship, scrambled to the scene within a half-hour. It joined multiple civilian boat crews that also answered the call.

The Seacor Power, owned by Seacor Marine, had foundered about eight miles off Port Fourchon, a coastal town nearly 100 miles south of New Orleans. The Glenn Harris rescued one person from the water, while another Coast Guard crew on a 45-foot boat found another survivor. Four others were saved by unofficial boat crews, the Coast Guard said. Watson said at the news conference Wednesday that one body was recovered.

At the time of the incident, Watson said there were 80-90 mph winds, 7- to 9-foot seas and “extremely limited visibility.”

“That’s challenging under any circumstance. We don’t know the degree to which that contributed to what happened, but we do know those are challenging conditions to be out in a maritime environment,” he added.

The details of the vessel’s journey and why it might have continued amid the challenging conditions remain unknown. Authorities said they are investigating those details, and communicating with the company and surviving passengers.

“We’re focused on the search-and-rescue effort more than anything right now, but those details will come out in the days and weeks ahead as we learn more about what went on,” Watson said.

When it departed, Watson said, the vessel was headed to Main Pass, about 25 miles east of Port Fourchon.

“We don’t, at this time, know exactly the mission they were on,” Watson said.

“Ive NEVER Heard soo many MAYDAY calls in my life!” a man named Bruce Simon, who said he was on a boat in the gulf at the time, posted to Facebook along with images of heavy seas. “Waves are breaking over the bow! A liftboat flipped. … An other boats have flipped an are taking on water!”

The Tuesday incident occurred as a slow-moving complex of intense thunderstorms, which had unleashed damaging gusts around New Orleans that toppled trees and damaged roofs, moved over the Gulf of Mexico. The National Weather Service issued a special marine warning for coastal waters around Port Fourchon at 3:57 p.m., warning that severe thunderstorms could produce gusts of at least 39 mph (34 knots) and large hail.

“Boats could sustain damage or capsize. Make sure all on board are wearing life jackets,” the warning stated. “Return to safe harbor if possible.”

A ship in the gulf headed for Port Fourchon recorded a gust of 117 mph (102 knots), according to Payton Malone, a meteorologist for WWL-TV, the CBS affiliate in New Orleans. A weather buoy at Grand Isle, about 15 miles to the northeast, clocked a gust of 75 mph and tropical-storm-force winds (of at least 39 mph) lasting for about an hour.

The intensity and duration of high winds appeared to be linked to a phenomenon known as a “wake low,” a small-scale zone of low pressure that can flank strong thunderstorm complexes. This allowed seas to build higher than they would have otherwise.

“It’s been a crazy day meteorological with very impactful winds from both a line of thunderstorms, and a long duration strong wind event due to a wake low,” wrote the Weather Service office serving the area around New Orleans on Tuesday night.

Severe weather was continuing to affect southern Louisiana and adjacent waters Wednesday. The Weather Service highlighted the region for an elevated risk of both severe thunderstorms and flash flooding.

Watson said crews were “actively searching,” even as difficult conditions continued with up to 8-foot seas.

“I won’t tell you those conditions can’t be challenging but we are out there and we are committed to this search and rescue effort,” he said.

On Wednesday afternoon the Coast Guard said in a statement that “rescue crews have searched more than 1,440 square miles, which is an area larger than the state of Rhode Island.”

Officials said throughout the morning, they received numerous calls from others in the maritime industry wanting to help.

“It’s been tremendous,” Watson said. “Both on surface assets as well as air assets, they’re wanting to get involved and we’re actively coordinating with those folks. So I want to say thank you to those folks.”

Archie Chaisson III, the Lafourche Parish president, told The Washington Post on Wednesday morning that some family members of those onboard the capsized vessel had arrived at Port Fourchon on Tuesday night. Seacor is coordinating communication with families and next of kin, according to the Coast Guard.

“We continue to pray for the men on the vessel and their families and rescue operators that are out, that we can bring everyone home safely,” Chaisson said.

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