In the far north of Regerwa winters seem to last forever. The snow and ice lay thick and the ground is frozen solid. One of the problems this brings with it is the burial of the dead, it isn't easy to dig deep enough in these conditions. As most people adhere to religions that prohibit burning of bodies here that is also not an option.
The solution to this problem is what is now known as The Great Burial. In the beginning of summer (since there is practically no spring), there is a great festival where all those who have died during the winter are celebrated and buried.
When people started to settle in the north they had to adapt to the freezing climate. In the northern-most parts of the world the seasons shift fast and drastically. Winter covers the lands in white for the better part of the year, spring is practically non-existent and summer short.
As their traditions call for ground burial of their dead a lot of different ways have been created through time to deal with this. Great Burial ceremonies and similar can be dated back a couple of hundred years by now. As freezing the body during the winter is not a problem, storage is easy and done with a lot of care. Then when the weather gets warmer and heats up the ground, graves can be dug and the dead buried.
In the beginning this was done by families on their own but as settlements grew and more dead was stored for summer it slowly transformed into the communal festival it is today.
During the winter months bodies are kept in special buildings that are more open to the cold than living houses, and a lot of effort is put into making these places beautiful during this time. When the ground has been thawed for one week they start to prepare for the festival, something that usually takes several days with cooking of food, decorating and digging graves.
As the festival begins all the bodies are decorated by their own families and then brought out to the grave field. Songs are sung, special ceremonial dances are performed and the religious ceremonies done. The bodies are then buried all at the same time and when it's done everyone gathers for a huge meal while remembering and honouring the dead.
That was a weird summer festival. I really liked the idea though! You mention people belonging to different religions, perhaps it'd be interesting to see what each of those religions thinks of death and the proper burial methods. It could be a good addition to the sidebar. One thing that I think should be clarified is whether there is one massive grave, or individual graves are dug for every person that died during the festival.
I will definitely be adding to this article later on, I liked the concept myself but the reason it is vague is because I haven't actually worked out the religions in the area yet haha. It's a very good point that I need to remember though! Oops, that definitely needs to be clarified, that was probably me writing too fast. Thanks for pointing it out!