Thanks for the reply! I did go and let them fly today. I dont think its Varroa because the mite levels were low this year. lower than the year before. But did treat them anyway.
One thing I did notice today that they were clustering outside the entrances, with there proboscis out as if trying to find something and few of them were flying away and drying in the snow.
Later, I put a tablespoon of water up to the cluster and they licked it up in about 30 seconds and then went back into the hive.
Would that indicate that they are out of food or a water shortage?