Two wolves will devour the sun and the moon; a crowing rooster will awaken the dead; and the Midgard serpent will start writhing toward dry land.  
Three consecutive winters will follow each other with no summers in between.  Two wolves will devour the sun and the moon; a crowing rooster will awaken the dead; and the Midgard serpent will start writhing toward dry land.  FTP, these event will take place when what apocalypse of Norse mythology occurs?
Three consecutive winters will follow each other with no summers in between.  
Ragnarok or Gotterdamerung