The fog that lingered over Metro Vancouver from Tuesday until Saturday appears to be responsible for two serious accidents in Surrey that sent a four people to hospital.

Two pedestrians were hit just after 7:30 p.m. Friday while crossing at 128th Street and 80th Avenue in a marked crosswalk. Surrey RCMP said both pedestrians were rushed to hospital with serious injuries. They said the driver of the Jeep remained at the scene and is cooperating with police.

Alcohol and drugs did not appear to be factors.

Earlier that day, at least two vehicles were involved in a collision at 104th Avenue and 141st Street. One vehicle ended up resting on the divider and another on its side. A witness at the scene told CTV News he saw two people being taken to hospital.

Environment Canada issued a fog advisory for Metro Vancouver that it refreshed just after 4 a.m. on Saturday.

"A strong ridge of high pressure continues to prevail over B.C. today," read a statement from the agency. "Moisture trapped under a temperature inversion is resulting in extensive area of dense fog."

Fog advisories are issued when visibility is expected to be close to zero. Environment Canada said the fog should start to become patchy Saturday afternoon.

With a report from CTV Vancouver's Ben Miljure