The first video of Gelateria Italia burning yesterday (Tuesday) in White Rock, BC (from White Rock Live) shows an interesting scene. At about 8 seconds into the video a fire officer points to the structure and orders the firefighters at the front of the building to move. Within 10 seconds the fire flashes followed by the wall on Side B (or Side 2) pushing out. It also appears that a firefighter on the roof of the exposure points out the imminent collapse. I know I am making some assumptions here, but either way it’s worth watching. News coverage here.
https://www.youtube.com/watch?v=JubDzqTP8wU
https://www.youtube.com/watch?v=Cba0L_AB8-M