Environment Canada has issued a fog advisory for Metro Vancouver.

Patches of dense fog developed in the early morning hours on Saturday. 

The fog was especially dense around several main roads in the region, including Hastings street in Burnaby, parts of downtown Vancouver, and along King George Boulevard in Surrey.

The fog also developed to near zero visibility along major highway routes, such as the Port Mann, Lions Gate, and the Pattullo bridges.

Fog advisory issued for Metro Vancouver, January 2, 2016

Heavy fog on Kingsway and Knight St. made for poor visibility early this morning. (Gian-Paolo Mendoza/CBC)

Environment Canada warns that fog, combined with below-freezing temperatures, can result in heavy frost and slippery roads.

Motorists are urged to slow down, watch for tail lights, and be prepared to stop.