Metaphysical / Paranormal event
The exact cause of the catastrophe is unknown, but it's effects are still felt to this day, it is described in short and tattered phrases, that the sky turned into a sea of colour, how the realms flickered, the walls of houses twisting and turning with the people inside, how the world withered away, and great storm surged across the land, for twenty years the storm raged, and where it went it brought with it the desolate waste, the green grasses turned to sand and people turned to beast, only where the mages gathered could the storm be held back.