The mountain of twisted metal and debris scattered along the Trans-Canada Highway in the Alberta Rockies looked like the scene of a plane crash to crews who worked Thursday to carefully pry apart wreckage from a spectacular chain-reaction collision involving five semi-trailer trucks.

Three people in one vehicle died and five others received non-life threatening injuries when five, fully loaded transport trucks collided around 9 p.m. Wednesday along a narrow, dark stretch of single-lane highway about two kilometres west of Lake Louise in Banff National Park.

“One like this, it’s a little bit like a plane crash because those trucks just came apart,” said Douglas Kerr, area highways manager for Parks Canada on Thursday.

“I’ve seen many accidents involving transport trucks but to have five of them at the same time in the same location is quite unusual,” he said.

The curving stretch of highway that winds through some of the most spectacular mountain scenery in the Rockies was strewn with a chaotic jumble of debris from the crash — the impact so great that material being hauled by the trucks was flung about 350 metres, he said.

RCMP are still investigating what may have caused the collision in an area that is used as a main route for transport trucks.

Investigators know that all the vehicles slammed into one another within the space of a few minutes.

“It appears the first west-bound semi lost control and jackknifed across the road which caused a collision with an east-bound semi,” said Constable Brad Malacko.

“From there a second west-bound semi collided with the two first involved in the impact, then a second east-bound semi collided with that,” he said.

The driver of a fifth semi managed to avoid hitting the tangled pile of transport trucks but struck some debris and hit the ditch, Constable Malacko said.

The road conditions at the time weren’t particularly icy and the area had not had snow in the 24 hours before the collision, he said.

Police are investigating whether excessive speed or mechanical issues may be factors. Constable Malacko said it’s not believed the driver of the first semi fell asleep or slammed on the brakes to avoid wildlife on the road.

“He was probably going a bit too fast for the road conditions,” he said.

No names have been released and RCMP are refusing to say which provinces the trucks may have been from.

The highway was closed after the collision and remained closed Thursday while crews worked to clear the debris.

One trucker was airlifted to hospital in Calgary, suffering from broken bones, another was taken to hospital in Banff and was then released, while three others were treated on the scene for scrapes and bruises, Constable Malacko said.

“Basically we’re in the mountains and we have winter driving conditions. People need to drive for winter driving conditions,” Constable Malacko said.

The operators of at least two front-end loaders brought in to help clear away the debris had to carefully avoid toppling into steep ditches on either side of the highway filled with nearly two metres of snow, said Mr. Kerr.

“It’s a fairly confined area so there’s only so much equipment that you can operate at a scene like this,” he said, adding he hasn’t seen the crash site, but workers provided him with detailed descriptions.

The loaders slowly jockeyed back and forth across the narrow highway, scooping up bucket-loads of cultured stone which was flung out of one of the trucks and onto the road.

“A lot of it is unsafe, so you just can’t go in there and start working. You’ve got to understand what may still fall down,” said Mr. Kerr.

“It’s a lot of steel … so you’ve got to be very careful when you send people in there that they don’t get in there trying to deal with it,” he said.

Four large wrecking trucks and several tractor-trailer units hauling flat-bed trailers were brought in from as far away as Golden, B.C,. and Calgary to pry apart the cabs of the badly damaged semis and haul the debris away.

Tractor trailers like the ones involved in Wednesday’s collision can weigh as much as 63,000 kilograms and be almost 17 metres long, Kerr said.

Road conditions at the time of the collision were in fair to good winter driving condition and the road, which had compacted snow, had been recently sanded, Mr. Kerr said.

There’s a high proportion of commercial transport trucks that use that stretch of highway and Kerr estimated 8,000 vehicles per day use it.

The posted speed limit in the area is 90 kilometres per hour.

Emergency crews, including RCMP, volunteer fire departments and ambulance crews from Lake Louise and nearby Field, B.C., had to work in inky blackness Wednesday to find the bodies of the three people who were killed, and to extract the injured from the wreckage.