The only thing I did has gotten me in hot water with quite a few folks.. I put my granulated sugar on the hive when I wrap it in November, JUST in case I can't get into the hives..
THIS winter.. I DID manage to get into the hives in February, which I was beginning to think I wouldn't.. However.. Every hive had already burned through 100 to 120 lbs of reserves and were halfway through the sugar I had put on.
Most years, if I can get into the hive in February, they are not yet at the top. Most years I remove sugar and make syrup with it in mid March...
In discussing the situation with other beeks at three different meetings/clubs (a fourth tomorrow night) and seeing a 70% loss across the board, I can only guess that everyone's bees burned through a LOT more reserves than normal, and those without an excess starved. Those with an excess, or those that were more frugal with their resources survived..
We had about a week of NASTY weather with 50 mph gusts and -20 temps.. We had several weeks of -12 or colder with 20+ mph sustained winds..
Normal here is about two weeks of sub zero with 12 - 15 mph sustained winds.. the rest of the winter hovers around 0, with regular breaks to just above freezing, sometimes as warm as 40... a few years back, in Mid January my wife and I were riding our horses on a 60 degree day.... I can only guess that people have become complacent and no longer prepare for the worst, and this winter bit them pretty hard.
Putting sugar on in November has gotten me flamed pretty good on other forums.. I considered finding those threads and asking those most aggravated by my method how their bees did.. but I will refrain... What I did worked, right or wrong, so I am one happy feller right now.