An overturned semi at a busy Winnipeg interchange tied up traffic early Monday evening. 

The accident occurred around 5:00 p.m. Monday, on southbound Pembina Highway at the Perimeter Highway.

A semi tipped on its side and spilled its load. 

Bystanders at the scene were uncertain as to what caused the accident.

Southbound traffic on Pembina was bumper to bumper as emergency crews attempt to right the semi. Traffic backed up all the way to University Crescent while the scene was cleaned up.