I am looking for a more or less universal backpack that would be suitable for the backcountry in winter. I realize that there might be no "universal" options so I am open for advice.

Specifically, I need a backpack that is good both for 1-2 night hut trips as well as single day backcountry skiing.  The ideal backpack need to have easily accessible avy gear (shovel, probe) compartments that are separate from the main compartment. It should be large enough, or coukld be extended to incorporate a sleeping bag, extra layers, sleeping pad, tarp, Jetboil or XGK, food and water, and be light/small/compressible enough for single day outings where sleeping bag is not needed. 

Currently, I have two backpacks. One is Osprey Aether AG 70, which is comfortable and has enough space, and does work well in multi-day 3-season backpacking, but is not designed for storing and quick deployment of the avy gear, and, I suspect, is not comfortable to ski with. My second backpack is Salomon S-Lab X-Alp 30, which is very lightweight, but is little more than a sack with straps. It does have the pocket for a probe but the shovel blade doesn't fit well inside, and also, 30 liters is not that much for winter trips beyond single-day excursion.