Divers are searching Friday for four people still missing after a duck boat packed with tourists capsized in high winds on a southwest Missouri lake, killing at least 13 people.
Missouri State Highway Patrol Sgt. Jason Pace said 14 people survived, including seven who were injured when the Ride the Ducks boat sank on Table Rock Lake in Branson Thursday evening.
Patrol divers found two more bodies early Friday, raising the death toll from 11 to 13, Pace said.
Stone County Sheriff Doug Rader said Friday that investigators still don't know what made the boat capsize, but he said Thursday that stormy weather might be to blame. Another duck boat on the lake made it safely back to shore.
It is unclear whether anyone on the boat was wearing life jackets during the time of the accident, but Rader said life jackets were on the boat. Divers located the boat, and the sheriff said they would recover it later on Friday.
Missouri Governor Mike Parson thanked first responders, volunteers and dive teams during a press conference on Friday morning. "Our thoughts and prayers are with the families and the victims in this tragic event that's occurred down here," said Parson.
Parson committed all state resources to help in the investigation. Both the Coast Guard and National Transportation Safety Board are assisting.
Passengers on a nearby boat told ABC's "Good Morning America" that the water became rough as the wind picked up.
"Debris was flying everywhere," Allison Lester said in an interview Friday.
Lester's boyfriend, Trent Behr, said they saw the body of a woman in the water and helped to pull her into the boat. He said he was about to start CPR when an EMT arrived and took over.
A spokeswoman for the Cox Medical Center Branson said four adults and three children arrived at the hospital shortly after the incident. Two adults are in critical condition and the others were treated for minor injuries, Brandei Clifton said.
Steve Lindenberg, a National Weather Service meteorologist in Springfield, Missouri, said the agency issued a severe thunderstorm warning for the Branson area Thursday evening. Lindenberg said winds reached speeds of more than 60 mph (100 kph).
Capt. Jim Pulley, owner of Sea Tow Table Rock Lake, told the Springfield News-Leader that the winds pushed the duck boat that capsized behind a steamboat that was tied to the dock.
Rader said an off-duty sheriff's deputy working security for the boat company helped rescue people after the boat capsized. Dive teams from several law enforcement agencies assisted in the effort.
President Donald Trump tweeted his condolences Friday, extending his deepest sympathies to the families and friends of those involved.
Suzanne Smagala with Ripley Entertainment, which owns Ride the Ducks in Branson, said the company was assisting authorities with the rescue effort. Smagala added this was the Branson tour's only accident in more than 40 years of operation.
Branson is about 200 miles (320 kilometers) southeast of Kansas City and is a popular vacation spot for families and other tourists looking for entertainment ranging from theme parks to live music. An EF2 tornado that bounced through downtown Branson in 2012 destroyed dozens of buildings and injured about three dozen people, but killed no one.
Duck boats, which can travel on land and in water, have been involved in other deadly incidents in the past. Five college students were killed in 2015 in Seattle when a duck boat collided with a bus, and 13 people died in 1999 when a duck boat sank near Hot Springs, Arkansas.
The City of Seattle recently settled 12 lawsuits with victims of the deadly 2015 duck boat crash on the Aurora Avenue Bridge. Mark Firmani, a spokesperson for Ride the Ducks in Seattle, says the operation in Branson is separate from Seattle.
Safety advocates have sought improvements since the Arkansas deaths. Critics argued that part of the problem is that too many agencies regulate the boats with varying safety requirements.
Duck boats were originally used by the U.S. military in World War II to transport troops and supplies, and later were modified for use as sightseeing vehicles.