I live on the metric side of the Atlantic. Winter means extra tension on wires, extra load on trees leading to higher risk of air lines broken. At the same time you have decreased number of man-hours in a day, decreased efficiency in those hours and difficulty reaching points of failure physically. This leads to high stress on maintenance in an event of a snowstorm. Depending how inclined your country is to vote for the MBA-style policies, there are chances your maintenance crews are already at near-capacity and therefore such an "adversary" event can easily lead to some a bit more remote areas left without electricity for a week at -20°C. Having A+++ house with photovoltaic cells will not help in that case.