A 62-year-old woman was been taken to hospital with life-threatening injuries after being hit by a snowplow at the intersection of Steeles Avenue and Leslie Street.
Paramedics were called to the scene just after 6:30 a.m. Tuesday.
The pedestrian was struck by a snowplow and investigators are still trying to figure out how that happened, police said.
Steeles Avenue East is now closed between Leslie Street and Waggoners Wells Lane for the investigation.
The collision reconstruction team is now on scene, and police say road closures will likely be in effect until noon.