Tester and test conditions
I am 184 cm tall and the backpack fits very well. I tested it last winter from February to April, mainly on ski tours, but it was also used for a day or two in the ski area.
Test report
Although the backpack is very compact, the packing volume is also sufficient for material-intensive day trips. In addition to the usual small items, I was also able to easily pack an SLR camera with two large lenses into the backpack. There is still room for an extra shirt, a warm down jacket or crampons. However, things get a little tight on high-altitude ski tours. In addition to the fact that an ice axe can only be attached to the ski straps as a makeshift solution, space is tight, especially on the ascent, when you have to stow crampons, most of your clothing, helmet, rope and harness in addition to the usual ski touring equipment. Due to the limited options for attaching equipment to the outside of the backpack, it is also difficult to "overload". I therefore recommend it primarily for "normal" use on ski tours and for freeriding. The carrying system is also not designed for overly heavy loads, but is easily sufficient for the backpack's main purpose. I initially had some concerns about the unpadded hip belt, but in practice this is easily sufficient even for a fully packed backpack. The padded shoulder straps and the stiff back plate not only distribute the weight well, but the backpack also sits close to the body in every situation, which is really great, especially on descents or jumps.
I also like how "tidy" the backpack is on the outside. If you remove the straps, nothing really hangs around and the Alpha SK looks more like a business backpack than an outdoor model. You can also leave it on in the chairlift, for example, as the backpack is hardly bulky due to its narrow shape. If you want to attach skis, a snowboard or something else, you will of course need the straps. The fastening works well and is also very quick thanks to the straps, but the skis sit slightly more wobbly on the backpack than with other fastening systems, which I put down to the fact that the straps run all the way around and this sometimes creates a certain distance between the skis and the backpack. I've gotten into the habit of stowing the straps in the emergency equipment compartment when not in use, as they open permanently when empty and then hang relatively loosely around the backpack.
Access to the main compartment via the lid works well, even when wearing gloves. In normal use, however, I have almost always used the side zipper, as it allows me to quickly and easily access items packed further down in the backpack (especially my camera). But the lid can also be opened quickly and easily.
When closing the lid compartment, you have to be a little careful that you really close it optimally, otherwise something can get inside the backpack, especially in deep snow. But once you've got that out, the contents are very well protected from moisture, which is of course also due to the waterproof material.
The AC² material, which is already known from various Arc'teryx backpacks, also proves to be very robust in continuous use. Branches, rocks or ski edges leave practically no marks on the backpack, so you should be able to enjoy it for a long time (I still enjoy using my Arc'teryx Arrakis, which is made from the same material).
