The Alberta family of Valerie Rusk, the Whitehorse woman who died with her family of apparent carbon monoxide poisoning, will travel to the Yukon for a memorial service on Saturday.

"I think the wife and I are still in shock," her father Ken Walters said Wednesday at his home in Warburg, Alta, a village about 90 kilometres southwest of Edmonton. "I don't think the real effect of it has hit us yet."

Rusk, 37, her husband of 14 years, Brad Rusk, and their two children, Gabriel, 13 and Rebekah, 11, were found dead in their home on the weekend. A boarder in the house, 47-year-old Donald McNamee of Markham, Ont., also died.

Brad and Valerie Rusk, and their children Rebekah and Gabriel, were found dead of apparent carbon monoxide poisoning in their Whitehorse home this week. (Courtesy of Ken and Evelyn Walters)

Walters and his wife Evelyn are devastated by the loss of their daughter, grandchildren and son-in-law. Walters, who broke down in tears at several points during his interview with CBC News, is left with many questions about the deaths.

"How could this happen and why did it happen?" he asked. "You always read in the newspaper or see on the news where these tragic events happen ... you never, ever, ever think that it could happen to you."

The Rusks moved from Sherwood Park, Alta. to Whitehorse four years ago so they could take advantage of the city's outdoor lifestyle.

Valerie was employed by a financial company while Brad worked on contract for the territorial government. Gabriel had just started at a new school and Rebekah loved to dress up and fish with her grandfather.

Flowers and candles could still be seen in the snowbank outside the Rusks' home in Whitehorse on Wednesday. Kevin Moore, a co-worker and family friend, said the couple was well-known in the community.

Ken and Evelyn Walters flip through family photos at their home in Warburg, Alta. (CBC)

"They helped a lot of people, they knew a lot of people, very, very close-knit family," he said. "Certainly Gabriel and Rebekah meant everything to the parents."

Investigators suspect an oil-fired boiler system may be to blame for carbon monoxide levels that were ten times higher than normal.

There was no carbon monoxide detector in the house and Walters wants people to install them in their homes.

"Probably before the end of the day I'll have one in my house," he said. "I advise everybody to put one in their house because you never know."

A memorial for the Rusks will be held in Whitehorse on Saturday. Ken and Evelyn Walters will be there, along with their son-in-law's family, who are also from Alberta.

They plan to hold a private service in Warburg.

With files from the CBC's Alicia Asquith