A fog advisory is in effect for Waterloo Region and Wellington County Wednesday.
Environment Canada issued the early morning warning and say visibility near zero is likely in some areas.
Combined with temperatures just below the freezing mark, the fog may deposit ice onto untreated surfaces and cause some roads and sidewalks to become slippery.
The fog played a role in a number of crashes on Wednesday morning.
Wellington Road 12 was closed for about two hours from Wellington Road 86 to Eighth Line as crews dealt with collisions and vehicles in ditches. Some rear-end crashes were also reported while the road was shut down.
Police said two people suffered minor injuries and were taken to hospital.
Conditions are expected to improve throughout the morning.
Those driving in the fog are asked to slow down, watch for tail lights, and be prepared to stop.
Fog advisories are also in place for Dunnville-Caledonia-Haldimand, Grey-Bruce, Huron-Perth, Oxford-Brant, Simcoe-Delhi-Norfolk, and several other communities across Southern Ontario.
