This story is a sequel to Agate's Vigil
Times change.
It's a slow process, usually. Over the eons, civilizations rise and fall, cultures change, new technologies get invented and become lost. For the individual person, such events happen too slowly to even notice.
However, sometimes, change is sudden and cataclysmic. A catastrophe forces people to take drastic actions, upending their known world completely. One such event happens to the three pony tribes in the form of the Long Winter, forcing them to flee their ancestral lands.
The vast majority of them flee southwards, with the exception of one earth pony clan. Past the steep northern mountains, the refugees are doing their best to adapt to their new surroundings and rebuild their homes. These are their stories.
A prequel to how the snowponies came to be. Each chapter is a separate story.