There is what appears under normal circumstances to be an uncrossable boundary, a total barrier.

zaffre:

Perhaps the finest part of it [the Lysjoch] is the grand sérac scenery of the Zwillinge Glacier. In August, 1876, a party of four, having missed the right track in crossing this pass when the snow was in very bad condition, were carried down in an avalanche of loose snow probably started by their own weight.

Like one day when I was just a shorty my mother was drinking a beer and a policeman told her to pour it out. He was way too little to be saying that to my mother. No way I was going to let him put handcuffs on her.