According to the Bakcheion ritual calendar Dionysos is MIA from Lampteria (when the Thyiades go searching for him with torches) until Lenaia (when the Lenai rouse him from his slumber beneath the earth with their songs and dances.)
Of course, part of him isn’t gone but always remains here with us (even if another part of him dwells down below with his feasting Heroes and Heroines.) The reason that he goes unrecognized during these bitingly cold winter months is because that fragment believes itself to be Óðr rather than Dionysos.
During this period he is reunited with his Norse wife Freyja and their nuptials are celebrated on December 31st into January 1st, which is also the anniversary of the creation of the Bakcheion, hence this festival is known as Foundation Day.
Our foundations lay in love, and madness, and ecstasy, and poetic inspiration – and so on this night we let the world know it through riotous displays and masked revelry.
How do you plan on celebrating?