One thing I did not make really clear, is this thread, is the real effects revised weather has on a BoA game.
On of the chief complaints with BoA, was that AI units (sometimes always on the go), would traverse wilderness aeras during the winter, to their own demise.
Apart from the season (WINTER), the real culprit in that situation, was the never ending blizzard conditions, that would cause damage to troops exposed to the weather front.
The fix, apart from what you see in the pics above, was to lower the incidence of Blizard and Fozen conditions in favor of Snow conditions. You still see units suffering HITS from harsh weather, but rarely a catestrophic army killing Blizzard, expect in Upper Canada, of course.