The right lane reopened just before noon on Monday following an earlier multi-vehicle crash that closed both eastbound lanes of Highway 1 at Prest Road near Chilliwack.
DriveBC is warning motorists to expect heavy delays through the area.
The crash, which involved seven vehicles, occurred just after 10 a.m. At least two people had be be extricated from their vehicles.
Four ambulances were on scene, as well has fire crews from at least two halls and RCMP.
An air ambulance was staged, but not launched.
Eastbound traffic was backed up as far as the Evans overpass.
Watch theprogress.com for more information as it becomes available.