In the words of VHB - What rhymes with overhang? - clearly the answer is 'doverschlang.'
This chart is courtesy of the VHB's private treasure trove of charts and data. It is a long-term chart tracking new housing supply through CMHC's starts, completions, and under-construction data. The area is the Vancouver Census Metropolitan Area.
What I find interesting here is that the 'under-construction' number has never risen above the completions number until 3 years ago. This leads me to believe that we are in unprecedented territory in the Vancouver CMA in regards to the potential supply overhang that is about to hit once all of the units under construction right now complete and the occupations take place. It is also interesting to note that normally the units completed falls approximately 6 months after starts fall (starts are falling right now) and normally the units under construction falls along with completions. This is not the case right now for whatever reason.
Remember that nearly every completion means another available rental unit or unit available for sale. Because population growth is low the demand must come from within the Vancouver CMA.
UPDATE: Area Breakdown
Look at all those units under construction. Crazy.