2 weeks when we had a warm spell I checked both my hives, one a top bar and one a langforth. Both were full and had stores. 3 days later I did not see any bees in the top bar. I opened it and found a handful of bees and no more. The hive was empty, leaving stores. Then I checked the langforth and they were doing great, then we had the cold snap again. I covered the langsforth with a blanket. After the cold snap I checked again and found brood on 5 cells about 3-4" diameter and dead bees over those cells, some emerging brood, larvae but all dead. Dead bees in the bottom. I think they froze. The top bar maybe has swarmed, but I didnt see any supersedure cells. The langsforth did have 2 cells and I found the queen on top of 1 bar dead. So unless I catch a swarm I am quitting I put too much into buying bees every year. I have 2 langsforth bodies and 2 to bar bodies and no bees. I have 3 swarm traps, empty.