Travis points to Great Big Sea’s blog (no permalinks, so it’s currently the second entry), where lead singer Alan Doyle describes how they rolled their bus:
The kettle hit Danny in the side of the head, spilling the hot water right next to him. I don’t know how he was not burned. The lurch to the left sent all of us flying to the right, where I almost kneed Kris in the forehead and did spill my coffee on his lap. I heard Bob smash against the walls of the washroom and watched Andy slide across the floor.
Then we started tipping.
‘Rolled’ may be a bit of a misnomer. I imagine you have to turn at least 180 degrees in order to roll. ‘Crashed and tipped’ might be better.
DarrenBarefoot.com 
Arieanna and I were at the concert. Alan Doyle started by saying:
“It’s good to be here. Really, it’s good to be here.”
And then they played an awesome concert.
Strange image produced in my mind by your headline. Happy, carefree Canadian guys swigging their Tim Horton’s, singing and clapping as their bus plunges over a cliff. Kind of the upbeat musical version of “Affliction.”