Games Workshop have posted an article with rules and suggestions for Mighty Empires Winter Campaigns.
From their website:
Winter campaigns in particular benefit from a strong narrative theme, as by their very nature, they are bitter and desperate conflicts, often fought as a last resort by the protagonists involved, though there are plenty of other reasons why armies can be gathered in winter. Elector Count Boris Todbringer led forth his Teutogen Guard at the head of an elite army of Middenheim in the harsh winter, chasing rumours of his nemesis, Khazrak the One-eye and his Beast Herd’s encroachment on his land from the Drakwald Forest. The stout soldiers of Middenheim, having long made their peace with the severe winters of their homeland, were well suited to a winter march deep into Drakwald in search of their quarry. Though Khazrak ultimately eluded his hunters, the well-prepared Middenheim army was able to endure the worst seasonal effects of the short campaign, and returned in good order back to the Faustschlag.
So, with your narrative ideas for a winter campaign hopefully bubbling over, let’s get to the juicy stuff and see how a Mighty Empires campaign can be fought in a winter setting.