The Royal Canadian Air Force, which was called out to rescue the group, said the incident happened near Toba Inlet, about 180 kilometres northwest of Vancouver.
The pickup was travelling on a snow-covered logging road when it went out of control and began sliding down an embankment.
Just before the truck went over a cliff, the four occupants jumped clear, but two of them were injured.
Medics from a company doing work in the area responded to the crash, but couldn't move the patients and poor weather prevented an air ambulance from getting into the site, so the Air Force sent in a Cormorant helicopter.
"There were already first responders on scene and they had provided us an exact location where they were," said aircraft commander Capt. Luc Coates in a media statement released by the Air Force.
"They had also cleared a landing site for us at a wide part of the road, making for a quick and efficient operation."
Once on the ground, RCAF emergency technicians linked up with the first responders.
"The patients were stable throughout and the medics had done a good job of keeping them warm and getting them ready for transport," said Master Corp. Justin Cervantes, SAR Tech on board the Cormorant.
The military chopper then flew the four people to a hospital in Comox on Vancouver Island.
Their condition was not immediately known.
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