Looking at your pics, I wonder too about the "granulated" looking stuff. Were you able to harvest any honey last year? And if you did, did it it crystalize?? Sometimes honey that crystalizes quickly, and if that is what is left in the hive for winter doesn't make for the best winter stores. Golden rod honey is notorius for this. If it is really cold it just seems like they don't consume it as well or something. Just one thought.
Also, I don't know about PA, but in WI we get those short "warm ups" too...warm enough that the bees start building up, but then it gets cold again. One thing I have learned with that is NOT to feed pollen patties in the fall. Wait until you can actually get in there in the spring.
I have also keep my slatted bottom board on all winter & use a ventilated top. Keeping your hives tilted too will keep snow from melting back into the hive & allow any condensation to drain out, rather than stay in & create more moisture.
Lastly, although it is disappointing when you have losses, don't blame yourself. It happens. Experiment next year & hope for a better outcome. If you have some beeks near you, see what they do for winter. So much is dependent on your local weather. Good luck & if you haven't done so, order a new package now or you might not get one. Good Luck!