January 23rd 1974

The event occurred on a cold night in the winter of 1974. There had been a terrible bang. The entire village heard it and thought something had exploded. Going outside, people saw blue and orange lights floating in a circle around Cader Bronwen, the mountain that rises to the east of the village.
As I wasn't there I cannot comment, however I've found a couple of pages regarding the incident, links below

For UFO crash details