A summery day on a Utah lake turned bad for a family and friends when high waves and violent winds kicked up and capsized their boat, throwing all seven people into the cold water.
Four died, including three children, as rescuers struggled to find the boaters for at least two hours in continual bad weather. The other three were eventually pulled from the choppy waters and hospitalized.
It happened on Monday at Bear Lake, which spans more than 290sq km in Utah and Idaho.
Utah doctor Lance Capener (46) took the ski boat out with his wife, Kathy (42), their two daughters and three of the girls' friends, authorities said. It was 26 degrees.
The group was reported missing at about 6pm, around the same time temperatures dropped and the national weather service tracked wind gusts of up to 82km/h in nearby Garden City.
The windstorm that rolled in over nearby mountains produced giant waves that also ripped to pieces a floating plastic dock at a nearby Scout camp.
All seven people on the boat wore lifejackets, but the water was 11 degrees, posing a serious hypothermia risk, authorities said.
The boaters were in the water for at least two hours amid waves that reached 3m as rescuers searched for them, Mike Wahlberg, Garden City fire chief, said. He called the conditions some of the worst he's seen and "about as extreme as it gets".
Rescuers reached the group and pulled them from the water, but Mr Capener died at the lake, Utah state parks lieutenant Eric Stucki said.
His daughters Kelsey Capener (13) and Kilee Capener (7), and their friend Sierra Hadley (13) were flown to a Salt Lake City hospital but died early on Tuesday.
Surviving members of the Capener family remembered the sisters as sweet and bubbly, they wrote in a statement.
Kathy Capener was hospitalised in the northern Utah city of Logan. Family friends Tiffany Stoker and Tylinn Tilley, both 13, swam for hours before being rescued. They were released on Tuesday.
AP