The bus had been coming from the north, and just a few kilometers back from this spot was a resort where Tour buses usually made their lunch stop. Obviously, the driver had missed the turn off to the resort (it really wasn't that well marked), and had decided to turn around at the first available spot. The silly part is, that the side road he had attempted to turn in, opened up into a big flat gravel pit so he could have simply driven in there and driven around, but instead chose to just pull into the side road, then back up, but unfortunately, he backed up too far so the rear tires were now down the embankment on the side of the highway.
We learned part of this while talking to a couple at this viewpoint, which over looks Pelly Crossing. This couple had had a small car, so could get around the bus, and they had taken the driver to the lodge.