Lowe Alpine uses an expanding volume design to make the Snow Attack 20 Backpack a solid choice for backcountry ski day trips. Its 1200cu inch main compartment expands by another 300cu inches when you open a single zipper. This allows you to pack an extra layer or snacks for your dawn patrol. The Snow Attack Backpacks diagonal ski carry holds your planks on the approach while the molded back panel supports the load. This Lowe Alpine pack also has a shovel pocket to keep your avalanche necessities available.