The accident occurred late Thursday night (July 19) in full view of witnesses, at least one of whom captured video of the small boat bobbing in rough waters on Table Rock Lake near the city of Branson, a popular holiday destination.
Police said 31 people were aboard the amphibious vessel, known as a duck boat for its wheels that allow it to ride on land and float low on the water.
The boat was seen struggling to reach shore against strong winds, before succumbing to the waves and beginning to sink.
The 17 people who died ranged in age from one to 70 years of age, and included the boat’s driver, according to the Stone County Sheriff's office.
Cox Medical Center Branson said six people were hospitalised.
The accident was caused by heavy winds as a storm moved over the man-made lake in southern Missouri. The duck boat was one of two in the water at the time. The other safely reached shore.
People on a nearby larger vessel, known as the Branson Belle, jumped into the water to rescue victims, Sheriff Doug Rader said.
“(Rescuers) got there quickly,” eyewitness Curt Elleman told MSNBC.
“The first rescuing was private boats... and they began pulling people out immediately,” he said.
The death toll quickly climbed as divers headed back in the water yesterday morning to search for four people that had yet to be found.
Divers located the boat in 25 metres of water, it had landed on its wheels.
The National Transportation Safety Board (NTSB) sent a team to investigate, as the sheriff urged witnesses to submit any additional video of the accident.
“My office has talked with NTSB,” tweeted US Senator Claire McCaskill of Missouri.
“They’ve got a large team heading out to Branson... and will have investigators there for a couple of weeks,” she said.
Among the unanswered questions were whether the boat crew was aware of weather warnings, and whether passengers were wearing life vests.
“From what I understand, there was life jackets in the duck (boat),” said Rader.
Rick Kettels, who owns the Lakeside Resort, said the storm formed suddenly at around 6:15pm local time.
“It just came up real quick,” he said. “I’ve been here most of my life and I never saw a storm this bad.”
Missouri meteorologist Steve Lindenberg said a string of severe thunderstorms had barrelled through the area.
Winds reached 119 km/h and a weather warning was issued at approximately 6:30pm.
The first emergency call about the boat was placed approximately 30 minutes later.
Branson, Missouri, is a vacation destination popular for its theatres and country music, including singer Dolly Parton’s Civil War-themed attraction.
As the southern region near the Arkansas border struggled to come to grips with the tragedy, the White House offered condolences.
“President Donald J. Trump and First Lady Melania Trump extend their deepest sympathies to all those affected,” press secretary Sarah Sanders said in a statement.
“Our prayers are with the victims and their loved ones. We are thankful for the brave first responders and dive crews, whose quick and decisive actions have saved many lives,” she added.
The company Ripley Entertainment owns the capsized boat, having added the “Ride the Ducks” attraction to its roster last year as a seasonal tour through the area’s famed Ozarks region.
The storm system that hit Missouri also struck much of the Midwest late Thursday, according to meteorologists.
Several tornadoes tore through Iowa to the north, causing injuries as well as damage to a number of buildings.
No fatalities were reported.