A fourth member of a Montreal family has died following an horrific crash east of Calgary on Wednesday.

CTV News has learned a fatal crash near Strathmore has claimed the life of 22-year-old Selena Plouffe.

She had been taken to Calgary's Foothills Hospital in life threatening condition by Air Ambulance after the minivan her teenage cousin was driving was hit by a semi.

A relative tells CTV News she had emergency brain surgery to relieve swelling, but when she was taken off life support her blood pressure dropped. Doctors put her back on life support so her sister could fly to Calgary from Montreal to see her. She was taken off life support a final time on Friday and died a short time later.

The crash happened around 4 p.m. Wednesday.

Cottage trip ends in tragedy

Seven people were in a minivan being driven by a 17-year-old boy. Six of the seven people in the van were members of the Plouffe family. They were driving back to Calgary from a trip to the cottage.

The minivan was proceeding through the intersection after stopping at a stop sign when it was t-boned by a semi that had the right of way.

Three people died on scene: the 17-year old driver, Travis Plouffe and his grandparents, Margaret and Paul Plouffe, both 75-years-old.

Four others, including Selena Plouffe, were taken to hospital in life threatening condition: Two girls from Nova Scotia, ages 12 and 13, were taken to Alberta Children's Hospital, and a 23-year-old man from Montreal, who is a family friend. 

The three survivors have been upgraded to stable condition.

The driver of the semi was not injured.

Police say the investigation is ongoing although they believe the crash was the result of human error on the part of the driver of the minivan.

The funeral service for all four members of the Plouffe family is being finalized.