Grande Prairie RCMP are on scene of a 20-vehicle collision on Highway 2, north of the city, police said in a news release Wednesday.
Emergency medical services and the fire department are also on scene, police said.
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 are currently blocked. Detours have been set up. Motorists are asked to avoid the area, or reroute via Emerson Trail, police said.
Delays are expected to take several hours.
STARS air ambulance tweeted Wednesday morning that it has been dispatched to an emergency in the area.