A massive pileup involving as many as 80 vehicles has closed down Highway 401 east of Oshawa.

An OPP  spokesperson reported that all westbound lanes of the highway are closed and traffic is being diverted.

It appears the worst part of the pileup is near Newcastle,  at the Highway 115 exit.

Constable  Linda Wolf said the weather conditions are far from ideal and have undoubtedly played a role in the accidents.

EMS officials say there is at least one injury that could be considered life-threatening, and several serious injuries.

Wolf said it will take quite a while to clean up the mess and get traffic moving again.