Hwy. 402 has been fully reopened following a serious 11-vehicle pileup in the Watford area.
Lambton OPP Constable Todd Monaghan says the multi-vehicle crash occurred just after 1pm in the westbound lanes just east of Nauvoo Rd. He says four people were transported to hospital by air ambulance with major injuries. Four tractor trailers and seven cars were involved in the crash.
Monaghan says OPP had to deal with about 100 vehicles stuck behind the collision. They were moved off Hwy. 402 at Forest Rd. and rerouted around the crash site.
According to the Ministry of Transportation, the east and westbound lanes have since been reopened.
Snow squalls off Lake Huron were causing poor visibility and whiteout conditions in snow and blowing snow through the afternoon.
Police were advising motorists not to venture out into affected areas until conditions improve.
Environment Canada has a snow squall warning in effect for north and east Lambton County.
The squalls are expected to continue into the early overnight hours Friday before dissipating.