The accident appears to involve a jack-knifed semi-truck and several cars. There are no reports yet on the condition of those involved, but several ambulances and fire trucks have been at the scene.
The highway was closed to all westbound traffic just past Gaglardi Way around 7:30 a.m. PT, creating backups to the Port Mann Bridge.
Crews appeared to be letting a single-lane of traffic stuck on the highway move out around 8 a.m., but all other westbound traffic was still being detoured off the route at Gaglardi Way.
Eastbound traffic is also limited to one lane, but is flowing.
The incident is the third time in a week traffic on the Trans-Canada Highway in the Lower Mainland has been shutdown during the morning rush hour.
On Friday a 17-vehicle crash on the Vedder Canal Bridge in Chilliwack closed the highway.
On Monday a ultralight plane clipped some power wires in a fatal crash, triggering the closure of the route.