I am a new beekeeper with only 32 hives which I purchased recently. We are in central Alberta and though weather has been very decent this weather we have not had much snow until now. 
Two days ago we had about 3 - 5 inches of snow and around a number of the hives I noticed many dead bees ( 50 - 100 ). Have others noticed this ?  and should I be concerned ? I have one book which states that "the intense light from snow covered ground tempts the bees to fly". What I observed was bees from a number of hives clustered around the upper entrance would fly out from the hive, land on the snow, struggle for a while then die. The book suggested shading the entrances with boards leaning on the hive which I have now done.
Any comments most appreciated.

Thanks
Bryan