A perfect Swedish family sits down to lunch on a restaurant terrace, high in the French Alps. Sun, snow, two blond kids. Then an avalanche rolls down the slope toward them, and for a few seconds it looks like it will bury the whole deck.

The mother throws herself over the children. The father grabs his phone and runs.

The snow stops short, harmless. Everyone shuffles back to the table. But it happened, everyone saw it, and FORCE MAJEURE (2014) spends the next two hours on the slow, excruciating, blackly funny collapse of a marriage over five seconds no one can un-see.

Ruben Östlund conceived the film after repeatedly watching a YouTube clip. Tourists at a mountain restaurant panic at an oncoming avalanche, then sheepishly return to their seats once they realize the danger was an illusion, ashamed of how they broke.

A friend supplied the twist that made it a movie: what if only the father runs, and only he has to walk back to the table?

Then Östlund went looking and found studies showing couples who survive hijackings often divorce afterward. He found that survivors of shipwrecks like the Costa Concordia were disproportionately men who saved themselves, leaving women and children behind.

The father-protector, it turns out, is often just a story we tell. Östlund half-jokes that you should watch the film as a relationship test, before you find out the hard way.