The road was slushy and the sky overcast Sunday afternoon as a white minivan carrying five people attempted to pass another vehicle on a narrow section of Highway 3 near Fernie.

Richard and Kunthea Altvater were heading home with their three children to Coaldale, Alta., when seconds later, at about 2:30 p.m., their van spun out of control, landing upside down in the freezing waters of the Elk River, trapping them inside. All but the mother survived, although one of the children was in critical condition on Monday.

“They lost control on the slush,” said Sgt. Don Erichsen, of East Kootenay Traffic Services. “You’ve got mountain on one side and river on the other. It’s a challenging section of roadway.”

The specific details of what happened after the crash are unclear, except that it involved a heroic act of bravery.

A couple driving by the accident scene stopped on the two-lane highway as the van flipped into the river. The man jumped into the frigid water, pulling each of the family members out one by one, bringing them to shore where his female companion waited to help.

Three of them were children under 10.

Once on shore, the couple was aided by Mounties and an American doctor, who offered CPR to a four-year-old boy and his mother, who was pulled from the front passenger seat.

The four-year-old and his brother, who is in serious condition but expected to survive, were airlifted to Alberta Children’s Hospital with severe injuries, Erichsen said.

However, the four-year-old boy, who on Monday was en route to Edmonton for more specialized care, is in critical condition with life-threatening injuries.

Their mother was pronounced dead at Fernie Hospital.

The children’s father and other sibling were treated for hypothermia at Sparwood Hospital, according to RCMP.

The unnamed rescuer, meanwhile, is asking for privacy. “He put himself in harm’s way. He put his life on the line and somebody still died,” Erichsen said. “It’s a traumatic event.”

In his 27 years on the job, Erichsen said he has seen very few people take such action. And while the man is undoubtedly a hero, Erichsen noted he didn’t jump into the swift-flowing Elk River for attention.

“He definitely risked his own life to do what he did,” Erichsen said. “From time to time, on rare occasions, thank God, this type of thing happens.

“Although we would like to think we would jump in and take action, it doesn’t happen all the time. It’s rare for people to do this and it’s definitely a commendation for those that do — it’s a pretty amazing act in my mind.”

Meanwhile, the small town of Coaldale is reeling from the tragedy.

Gary Scherer, director of operations for the town, said that while he wasn’t a personal friend of the Altvaters, he did talk to them occasionally and found them to be a very “positive, friendly and outgoing” family.

“It’s so sad,” said Scherer. “We (the town) are shocked. They always had gatherings at their home and they’re quite popular. They were a very young family and the children were always playing in the backyard.

“It’s tragic.”

ksinoski@vancouversun.com

With files from Mike Hager and Brian Morton