Environment Canada says dense fog can be expected in Waterloo region this evening before visibility clears on Wednesday morning.

On Tuesday just after 7 p.m., the weather agency issued the advisory for the Region of Waterloo and parts of Wellington County.

“Visibility may be significantly and suddenly reduced to near zero. If travelling, be prepared for areas of near-zero visibility. If visibility is reduced while driving, turn on your lights and maintain a safe following distance,” the advisory says.