There was a witch.  The villagers acted like douches.  Drove her out of town.  She put a curse on the place that made it so that the first caravan through the pass caused an avalanche, blocking the pass.<br/><br/>And something about missing childrens and bandits, although the bandits likely aren't directly caused by the curse.  If I had to wager, I'd do so as pegging them to be an ancillary result of the curse...  A bunch of people disagreeing with the actions of officials that ends up cursing them all ... could easily turn to banditry.