RCMP said the collision occurred in the southbound lanes of Highway 2, north of Emerson Trail near Highway 672. Both lanes of the highway were shut down for hours but have since reopened.
Photos from the scene showed dozens of smashed cars and injured passengers. Witness Pancho Driedger said he drove up on the accident scene shortly after it happened.
"I saw a bunch of, at least 40 vehicles just scattered across the road and into the ditches and lots of screaming," he said. "There was this young girl sitting on her moms lap and just bleeding really badly. She passed out a couple times. I went and put my jacket over her just to make sure she was warm."
The highway was closed as a result and emergency crews including a STARS Air Ambulance were responding.
STARS confirmed to CTV News Edmonton that an air ambulance was dispatched to transport one patient. The helicopter could not land close to the scene and a ground ambulance was used to transport one patient to a Grande Prairie hosptial in stable condition.
Driedger said others were in the ditch, injured and cold, and called the entire ordeal "traumatizing."
Fog in the area was reportedly thick when the crash occurred. Driedger said the area was near-zero visibility.
Shortly after 12:30 p.m. local time, Grande Prairie RCMP said Highway 2 reopened to traffic in all directions and that emergency crews were no longer on scene.
Grande Prairie, a community of around 63,000 people, is roughly 390 kilometres northwest of Edmonton.
511 Alberta said the crash occurred on Highway 2 at Highway 672 north of the city Wednesday morning. 1
Grande Prairie RCMP have re-opened Highway 2, north of the city, following a 20-vehicle collision Wednesday morning.
The crash occurred in the southbound lanes of Highway 2, north of Emerson Trail, about 20 kilometres north of Grande Prairie.
Northbound and southbound lanes of Highway 2 were blocked for more than an hour and detours were set up.
STARS air ambulance tweeted Wednesday morning that it has been dispatched to an emergency in the area.
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