I know the bees are alive because I saw a bunch of their dead today.
We have had such a mild fall this year. We had highs in the 60's clear into November. The last few weeks have turned cold and snowy, though. I hadn't seen the bees in quite a while and then the snow came. It blew into the entrances and froze in place so the bees had no way to get out even if they wanted to. I pressed my ear against the sides of the hives and knocked- last winter I could always hear a buzz coming from inside, but this time I heard nothing. I was a little worried that they were not ready for the cold snap and that something had happened to them. I shouldn't have worried- bees have been taking care of themselves for millions of years.
I took a walk over to the hives today and saw some good news- dead bees. With the warmer temps the last few days the ice in the entrances melted and the bees began clearing out some of the dead that had accumulated inside the hives. There were about 10 dead bees laying on top of the snow in front of each hive. As the winter progresses we will find more bees that die and are cleared out by the bees left inside. They are very hygienic creatures.