In severe cold I have seen a few bees do what I call a susicide walk. I believe, my assumption is the bees are going to die naturally, they know they are going to die, so they make an attempt to leave the hive.I am attempting to explain a phenomenon, my opinion, based on my observations. I am not stating a fact based on bonafide data.If there are a lot of bees, then this is different from my explanation. Maybe a desperate attempt at a cleansing flight.Blessings
I have also read accounts by old time beekeepers of this behavior. They believed that snow on the ground confused the bees into thinking it was a full sun day and it led to their death. I don't know of any scientific data on this penomenon though.