Hello from -40 F. in Western Interior Bush Alaska.
Wintering for us is a necessity.  A package of bees from the Lower 48 costs around $160.00+ just to get them flown out here plus we must meet them at the airplane in Anchorage and wait to transfer them to a Bush plane when available. We are 230 miles on the backside of the Alaska Mountain Range by Bush airplane from the closest road system in Anchorage.  We will have approximately 20+ days in the -65 F. temperatures this winter.  It has already been -51 F. and colder.  We currently have 2 1/2' snow on the ground. Last year we had about 12 1/2' snow total.  
Our German Shepherd guard dog lives outside near the hives all winter.  The Moose can cause lots of damage to a yard of hives!  The Grizz and Black bear can be an issue in the summer.
Beekeeping friends of mine up in the Delta area will have close to -80 F. with terrible winds and last year other friends in the Tok area had -80 F. one day followed by -81 F. the next.  This is not counting the wind chill factor.  They winter bees similar to us with results close to us.  
Our success in wintering has been as good as 100% and as poor as 50%.  We average about 20% loss in this location.  It takes 60+ pounds of honey left on the hive, candy boards, Power Patties, I.P.M. Patties, wrapping hives, banking them with snow, cleaning up the bees and hives without chemicals, and good wind free south facing locations just to have a chance of making it through the winter.  We like the darker bees for our area.  
We have tried root cellars as well as large ditches in the ground covered with timbers/plywood and then covered with 4' of earth and a 2" pvc pipe in and out, sheds, barns with straw piled high all over the hives, greenhouses, with the goats in their barn, etc.  
We are always experimenting looking for the perfect arrangement.  
We like our system as it works for us in our environment.  
We do remove 1/4 of frames each year.  We have no issues with Nosema; mites and foul brood are not issues in our yards.
We run between 300 to 500 hives in this particular location.
Merry ChristmasDr. Joe CarsonAlaska Heavenly Honey  

 		 	   		  
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