Kirk here with a beautiful unkai (雲海; sea of clouds) video from Aso (courtesy of the “Aso project” page). I’m not sure when this was taken but I think unkai is a very early-morning phenomenon. On days when the conditions seem to be right, photographers get up in the middle of the night (or don’t go to bed) so that they can be there at dawn – midday tourists aren’t likely to see something like this.