All westbound express lanes on Highway 401 are blocked near Milton following a five-vehicle collision.

Police say that the crash happened near Trafalgar Road on Friday morning.

A total of three transport trucks were involved in the crash, including one which has jackknifed across multiple lanes of traffic.

So far only minor injuries have been reported.

It is not immediately clear what led to the collision, though police say that roads in the area are treacherous due to a winter storm currently hitting the GTA.

“The roads are super slick. If you don’t need to be out here please stay home and wait for the system to pass,” OPP Sgt. Kerry Schmidt said in a video message posted to Twitter. “If you are on the roads drive with extreme caution and care. It really is challenging out here for driving.”

Police have not provided any timeline for how long the lane closures will remain in effect.