The occurrence of snow in the Seattle Tacoma area is extremely variable and usually melts before accumulating to measurable depths. There are winters on record with only a trace of snow but at the other extreme, over 21 inches has fallen in a 24 hour period.
The rabbit's sense of smell is far more developed than that of the human. Moveable folds inside the rabbit's nose assist in the detection of scent. The sense of smell in a rabbit is present at birth, allowing a newborn to find his mother's teat. Rabbits shift their noses up and down when trying to identify a scent; this is called nose blinking..
I have never seen a rabbit die from good sanitation practices. Ventilation- air should be moving to keep fresh air to your rabbits if it smells to you it smells worse to the rabbits. Apple Cider Vinegar- Use as an additive to their daily water giving it continuously or in 3 month cycles (3on, 3off, 3on,etc.). Dosage: Add 1 to 2 tablespoons of ACV to a gallon of water.