So much for global warming. The weather here is the same as yours, in Maine. It’s not terribly efficient, but you can melt snow and ice for water. If possible, boil it before drinking. Blackberries and blueberries grow here in the wild year round. Unless they are of a sort that only live in a hot climate, I think they’ll be okay. Congratulations on your newest addition. Have your entire brood sleep and mostly stay in one room, pets included if warm-blooded and able to be in the house. Combined body heat has been known to save lives. There are numerous stories of dogs staying with their masters who fell in the snow, being found alive after several days.
Praying for you! 🙏