This video I made a few years ago. The pics were from Jerry Linsers hive. He demonstrates one way to look at a hive on a cold morning. On a cold Jan 29th day. The bees were still peeking out the top hole of the top box.
It will be warm for the next couple of days. This is good timing after our long cold spell. With the warmer weather the bees can move their cluster easily and hopefully re-position slightly on a fresh frame of honey. This will prep them for the next cold blast later this week.
There should be no brood in a colony right now.
Bees will be going on cleansing flights over the next few days. It is a good time to see if your hive(s) are alive. There will be bees dying in the snow. This is normal.
If you don't see bees on cleansing flights, it doesn't mean that the hive is dead. If a colony was very heavy with honey especially a three deep hive. The bees could still be down deep in the box and can't break cluster to get out. You can rap on the side of the hive and listen for a buzz. If you get physical with the hive, a beesuit may be in order. An interloper could fly out and give you some payback for the disturbance.
Not seeing cleansing flights today is not a huge problem at the moment. As time goes on, the cluster will shift into the top box and cleansing flights will be more frequent with the warmer February weather.