Authorities have not yet identified the victims.
In Philadelphia, Pennsylvania, two Hungarian tourists were killed in 2010 when a barge hit a disabled duck boat in the Delaware River.
Since then, another accident seems to occur every few years.
"Oh my gosh, oh no", a woman is heard saying in the background of the video.
At least 13 people, including children, are confirmed dead after an amphibious "duck boat" capsized and sank in stormy weather on a lake in Missouri with 31 people on board. In their initial assessment, authorities blamed thunderstorms and winds that approached hurricane strength, and a full investigation was underway.
Soon, the sound of sirens filled the air, Burkhart said, and he and his wife left to get out of the way for first responders.
"Our number one priority is the families and our employees that were affected by this tragic accident", Suzanne Smagala-Potts, a spokeswoman for Ripley Entertainment, said on Thursday.
Seven people were being treated at a hospital, one of them with severe but non-life-threatening injuries, he added. The boats were returning to shore when the incident happened, he said. McClure said the company monitors regional and local radar hourly before tours.
"But it suddenly got very dark", he recalled. Dark, rolling waves crash over its front end.
McClure said the vessel, the M/V Bufflehead, recently passed its annual Coast Guard hull inspection and a stability test that allows it to operate in Portland Harbor with 36 passengers and two crew members. "He was at every event".
Children are among the dead, although authorities have not provided an exact breakdown of the victims.
The amphibious boat travels on both land and water, and is popular among tourists in major cities.
The company that builds ducks, Ride the Ducks International, agreed in 2016 to pay a $1.35 million fine after one of the vehicles collided with a bus in Seattle, killing five international students. Thirteen people died in 1999 when a boat sank near Hot Springs, Arkansas.
Video of the incident showed the hull of the vessel submerging into choppy waters.
The captain of the duck boat survived, but the driver of the vehicle was among the fatalities, Rader said. On the road, the vehicles ride high and take up a great deal of space, and it's hard for drivers to see what's around them.
High winds caused the boat to become laden with water and capsize.
"Debris was flying everywhere", Allison Lester said in an interview Friday with ABC's "Good Morning America".
Drivers of duck boats sit about 10 to 12 feet behind the bow, making it hard to see what's directly in front of them. He said he was about to start CPR when an EMT arrived and took over. It sank in 80 feet of water and was upright when found by divers.