CHICAGO (AFP, REUTERS) - Nine members of one family were among 17 people killed when a US tourist boat capsized during a sudden storm on a Missouri lake, relatives told US media on Friday.

The accident occurred Thursday night (July 19) in full view of witnesses, at least one of whom captured video of the amphibious vessel bobbing in rough waters on Table Rock Lake near the city of Branson, a popular holiday destination.

"My heart is very heavy. Out of 11 of us there's only two that's surviving, that's me and my nephew" Tia Coleman, her voice breaking, told Fox59 from her hospital bed.

"I lost all of my children. I lost my husband. I lost my mother-in-law and my father-in-law," along with other relatives, she told the Indianapolis TV station.

Coleman said the boat's captain had told passengers earlier in their trip that they "won't need" life jackets.

"He said it when we were in the water," she told Fox59. "When it was time to grab them, it was too late and I believe that a lot of people could have been spared."

She added that the water "didn't look ominous at the very first."

Police said 31 people were aboard the vessel, known as a duck boat for its wheels that allow it to ride on land and float low on the water.

The hybrid nature of such craft has previously raised safety questions.

The boat was seen struggling to reach shore against strong winds, before succumbing to the waves and beginning to sink.

The dead ranged in age from one to 70 years of age, and included the boat's driver, according to the Stone County Sheriff's office.

Stone County Sheriff Doug Rader told reporters that the boat's captain survived.

Several people were injured.

Two duck vehicles were on the lake and headed back to shore but only one made it.

Jim Pattison, president of Ripley Entertainment, which owns the Branson "Ride The Ducks" tour company, said the strength of the storm was unexpected, but the duck boat should not have been in the lake.

"It shouldn't have been in the water if what happened, happened," Pattison told the CBS This Morning show.

'NEVER SEEN IT LIKE THIS'

Pat Cox, owner of a marina about a half mile from where the vessel went down, sent five boats and some 20 people to the rescue. "These people showed an amazing strength maybe that we don't always give them credit for," Cox said by telephone. "They had it and they took action. And they were good Samaritans."

The first boat's crew was able to pull two people from the waves, Cox said. "It was all hands on deck. We did everything we could."

Branson is a family-friendly tourist destination with attractions like "Dolly Parton's Stampede" dinner theatre, the Amazing Acrobats of Shanghai and a Titanic museum with a model of the sunken vessel's front half.

Rick Kettles, owner of the Lakeside Resort General Store and Restaurant, said he had never before seen such conditions on the lake, which is a 174 sq km reservoir on the White River.

"I am 54 and I started coming here when I was 6 or 7 years old. I have been on my lake most of my life and I have never seen it like this," Kettles said.

"I am trying to figure out why the boats were out there. I don't get it, having a captain's license myself."

A microburst is a severe, localised wind gust, blasting down from a thunderstorm, typically covering an area less than 4km in diameter and lasting less than five minutes.

WORLD WAR II-STYLE VEHICLES

Duck vehicles, modelled on landing craft that were used in the D-Day invasion of World War Two, are used on sightseeing tours around the world.

The company that builds ducks, Ride the Ducks International, agreed in 2016 to pay a US$1 million fine after one of the vehicles collided with a bus in Seattle, killing five international students.

Thirteen people died in 1999 when the duck boat in which they were riding sank near Hot Springs, Arkansas.

Afterward, the National Transportation Safety Board warned that the boats'canopy roofs presented a hazard, making it difficult for people, even those wearing life jackets, to escape if one of the vessels capsized.

Two tourists died in Philadelphia in 2010 when the duck boat they were in was struck by a tugboat on the Delaware River.