The river was high.
The villagers heard another settlement upstream had been washed away. Several men took the responsibility of setting out in the middle of the water, on rafts, just in case anyone came drifting on by. Other schemed and planned and thought about they could retrieve anything of worth, and set on out on the three day journey north to see if anything remained.
The sun came out, and the river and the townsfolk went back to normal.
Except the men who went north, they refused to ever say what they’d found, or what found them, up there.