In the middle of cold and snowy winter, how would a beekeeper know if the bee colonies are alive and well inside the beehives?

It would be wrong to open the top lid and take a peek – it’s too cold and it could kill a healthy bee colony.

In cold winter months, in a honeybee colony thousands of bees assemble in a roughly spherical shape called winter cluster.

Such sphere spans several honeycomb frames and in its middle there’s a Queen bee while the older worker bees are towards the edges of the sphere.
The bees gradually consume available honey stores maintaining the temperature of around 95F (35C) inside their spherical cluster.
The older bees on the edges of the cluster gradually die off – it’s a natural process. When they die, they fall to the bottom of the hive and the cleaner bees keep moving the dead bees away, usually toward the entrances.

At my ForestBeehive apiary, at least every 2 weeks I check all entrances to see if there are a few dead bees out there.
When a few dead bees re-appear at the entrances, paradoxically, it is the evidence of a healthy honeybee colony, taking care of itself.