Missing hikers Greg Tiffin and Sophie Dowsley.

Sophie Dowsley, 34, and Canadian boyfriend Greg Tiffin, 44, have not been seen since their day trip to Statlu Lake, about three hours west of Vancouver, on July 8.

The couple vanished near a waterfall that has a history of fatalities.

Ms Dowsley is believed to have lived in Canada for about three years. Her devastated family have flown from Australia to Canada to help search for her.

“We just hope that they’re alive. We think in our heart of hearts that they might be. We just need to know,” her father Peter Dowsley told CTV News.

He said the couple had gone to “a very dangerous place” but hadn’t come out.

“The terrain is just absolutely stunningly beautiful and rugged and unforgiving. Obviously, the only people that can be in there are trained professionals,” Mr Dowsley said.

“It’s the worst possible nightmare that you could imagine. I couldn’t dream of anything worse.”

The only sign of the couple so far has been their SUV — but in a worrying sign, Ms Dowsley's sunglasses near a waterfall, and some of Mr Tiffin’s belongings were found in the water below the waterfall.

Friends are appealing for help in finding Sophie Dowsley. Picture: FacebookSource:Facebook

Canadian media reported the waterfall was a known danger area where there had been a number of fatalities. One experienced search and rescue official, Neil Brewer, told local media he hadn’t been there for about 20 years — and that was for a series of searches which all ended in tragedy.

Search and rescue teams are scouring the area. But Mr Dowsley told CTV he was worried a bushfire crisis in British Columbia was drawing resources away from the search.

“We understand that so many trained professionals are fighting fires in Canada and where the resources are going to come from to find our daughter, we don’t know,” Peter said.

Mr Tiffin’s brother Jeremy Tiffin said he would have gone into the hike prepared.

Jeremy Tiffin, Greg’s brother, said his sibling would have gone to the hike prepared, including the route he was taking.

Melbourne woman Lauren Wowk told The Herald Sun she had been chatting with Ms Dowsley with other friends in a group chat. They were aware she was going on a hike so weren’t too concerned when she didn’t hear from her in a few days.

“When they both didn’t turn up to work on Monday, the alarm was raised,” she said.

A Department of Foreign Affairs spokesman said the family was receiving consular assistance.

“The Department of Foreign Affairs and Trade is providing consular assistance to the family of an Australian woman reported missing in Canada, in accordance with the Consular Services Charter. Owing to our privacy obligations, we will not provide further comment.”