Highway 2 has re-opened in both directions following a multi-car collision triggered by heavy snow and ice in Leduc, south of Edmonton, on Thursday.
The spring blizzard blasted through the Prairies, killing three and causing a chaotic series of crashes.
A 23-year-old woman, a four-year-old girl and a two-year-old boy were killed Thursday morning when the compact car they were in crashed head-on with a truck about 180 km northwest of Edmonton. Three others were seriously injured.
Mounties say it was snowing heavily at the time and visibility was poor.
Just before noon, multiple collisions happened within a half-kilometre of each other.
Police estimate that as many as 100 vehicles were involved in the Leduc crash on Highway 2, and at least 45 vehicles were damaged.
"And from that collision we ended up getting a chain reaction, so multiple other collisions occurred from there, due to the poor visibility and the icy roads," said Const. Karolina Malik.
About 22 people went to area hospitals, including a man with serious injuries.
The RCMP said the man was outside his vehicle after being involved in a collision and he was found under a semi-trailer.
Kerry Williamson, with Alberta Health Services, said Thursday that about 80 others were treated at the crash site for minor to moderate injuries.
Paramedics, EMS crews and firefighters trudged through the snow, going from vehicle to vehicle, to check on those inside, Williamson said.
They commandeered three Greyhound buses on the highway and used them as triage centres, he said.
Police also escorted four Edmonton transit buses to the scene to provide shelter to motorists who were stranded.
STARS air ambulance had to turn down requests to ferry patients because of the bad weather, said spokesman Cam Heke. The helicopters simply couldn't get in the air.
RCMP closed a 60-kilometre stretch of Highway 2 — the main road between Edmonton and Calgary — and redirected traffic away from the scene.
Mounties in Saskatchewan also issued travel warnings and closed highways due to heavy snow, winds and icy conditions.
RCMP Regina Sgt. Doug Coleman said in a news release that people were stranded on the Trans-Canada Highway overnight Wednesday, and officers couldn't get out to get them until Thursday morning.
154 Via Rail passengers were also left stranded aboard a train travelling from Vancouver to Toronto Thursday.
The train was halted near the small community of Tako, about 190 km west of Saskatoon, due to bad weather and problems with one or possibly more Canadian National Railway trains down the line.
The company says the passengers have been getting food and supplies and were expected to resume travel Friday.
With files from the Canadian Press