Hi everyone-This is a great topic to discuss. I used to brumate in mini refrigerators (back in the 80's) and had the same problem Don had, high condensation and humidity. Water would accumulate on the bottom of the lid and drip and most of the snakes got blisters. Now I brumate in a room (basement) in the mid 50's to low 60's, w/ minor fluctutations in temps above or below these temps for short periods of time. I house them in their same containers as they are in during the summer, however everything is cleaned just b4 putting down (water bowl, container, new newspaper for a hiding area and substrate is thoroughly cleaned out of all fecal/urine matter). Basically I set them up in a pristine conditions so to minimize the chance of die off. I used to check them monthly, until I had one that flipped a water bowl over and had a severe blister problem. Now I check them every 2 weeks, adding h20 to their water bowls if low, using heavy duty bowls so they can't flip them over. Some still manage to get the substrate wet, in which case I replace the entire cage's substrate. Wet substrate left for long periods of time can induce mold, which can be fatal. I do try and handle the snakes as little as possible when checking them however I have taken pics of them in the winter time, and if using caution, can do this w/ seemingly no ill effects. It's a lot easier to take their pics when brumating as they are much more lethargic, some do lose their colorful luster while hibernating though (infernalis, similis in particular).

All this being said, I have lost a handful every year, this year has been minimal so far (knock on wood). Baby garters seem to be extremely susceptible to die off if brumated in their first year (no clue why this is). If babies go off feed I put them down for 3-4 weeks (adults are down for about 4 months) and bring them back up. This has worked well and minimized neonate attrition immensely.