Charges have now been laid in connection with a fatal three-vehicle crash in Thornhill on Monday afternoon, York Regional Police say.

Police said two sedans collided with a large box truck in the area of Don Mills Road and Simonston Boulevard, near Paddock Park, at around 1:30 p.m.

It was initially reported that one person was critically injured in the crash but in an update on Tuesday morning, police confirmed that a 33-year-old woman was pronounced dead at the scene.

"Through investigation it was learned that the truck was traveling southbound when it crossed the centre lane into oncoming traffic, striking two vehicles," York Regional Police said in a news release issued Tuesday. 

The driver of the truck, identified by police as 55-year-old Caledon resident Trevor Hepburn, has been charged with impaired driving causing death and dangerous operation causing death, investigators said.

Police said they are continuing to search for witnesses to the crash or anyone with dash camera footage of the area at the time of the incident.