EDMONTON -- A Saskatchewan man who survived the deadly tour bus rollover at the Columbia Icefield over the weekend — and whose girlfriend was killed in the crash — is recounting the terrifying incident.

Devon Ernest, his cousin Wyndi Ernest, and his girlfriend Dionne Jocelyn Deroucher were on a tour of the icefield Saturday when their bus slid off the glacier, plunging 50 metres before landing on its roof in an embankment.

"Heard the front wheels kind of slide off the mountain and the last thing I see is the roof," Ernest recalled Monday.

"I woke up beside my girlfriend and she was breathing, she was OK, and then it looked like she was having a hard time breathing," he said.

Ernest then ran to his cousin to make sure she was OK, despite having a hard time breathing.

"When I went running back to my girlfriend, she stopped breathing and closed her eyes, and that was it," he said. "After that they gave me a blanket and I just cuddled with her until the guys came and got me out of there."

He estimates he was trapped in the wreck for about half an hour.

Deroucher, who was from Canoe Narrows, Sask., is one of three victims who died in the crash. A 28-year-old woman from Edmonton and 58-year-old man from India also died. Two-dozen people were injured in the crash, with four remaining in critical but stable condition and one in serious but stable condition on Monday.

Ernest said his cousin was sent to hospital in Calgary with a fractured vertebrae, broken ribs, a fractured neck and a fractured shoulder blade.

Ernest suffered a head injury but expects to make a full recovery.

The reason for the rollover has not been determined, but RCMP said Monday there's no evidence it was caused by a rock slide.

Officials said it could take several days to remove the ice explorer vehicle, due to challenges presented by the embankment it fell into.

Ernest, who is now grappling with his loved one's death, has his own questions about what happened — and why.

"Why isn't there seatbelts? No safety procedures on there. All they cared about was a tour," he said. "Are they going to put seatbelts after this? I don't know. Does it take three, four lives for them to put seatbelts on?"

He also regrets ever bringing his girlfriend and cousin in the first place.

"All I could think was 'I'm so sorry I [brought] you here, it was my fault. This was supposed to be a good time here," he said.

Deroucher, his girlfriend of two years, was the light of his life who took care of him when he needed it.

"She was the most loving person," he said, becoming emotional. "She always cared for everyone. Mostly me when I got my migraines, she was there to rub my head, my back. Even if I acted like a big baby with a little headache she'd still come love me…I'm alive today because of her."

The tour bus company, Banff Jasper Collection, said it is conducting an internal investigation into the crash and will make any changes that are recommended, which could include mandated seatbelts.

Company president Dave McKenna said in 39 years of service, there have never been any major incidents or deaths on a tour until now.

"We will wait until the investigation is over and we will listen to all the recommendations and anything we're required to do, but we'll listen to everything and we'll certainly act on those once the investigation is through," he told CTV News Edmonton.

The ice explorers are off-road vehicles that aren't licensed to be on the road and are designed to operate on the glacier's slick terrain, he said. They do not exceed 40 kilometres an hour and do not have seatbelts.

Police are asking travellers to stay clear of the Icefields as they continue a joint investigation with Occupational Health and Safety and the Transportation Safety Board.

Anyone with information about the crash is asked to call Alberta RCMP at 780-852-3883.

With a report from CTV News Edmonton's Sarah Plowman.