A woman is in critical but stable condition in Victoria General Hospital after the van she was driving collided head on with a semi-trailer on the highway between Port Alberni and Parksville.Port Alberni RCMP Const. Theresa Thompson said the collision occurred Thursday on the Hump a long slope on Highway 4 outside of Port Alberni. The woman was alone in the van and headed east, toward Parksville.The other driver was not injured, Thompson said.The crash resulted in a fire that passersby helped to extinguish, she said.There were off-duty firefighters who stopped and assisted.Port Alberni fire crews were also dispatched.