The styles, shapes, and sizes of backpacks are virtually limitless, not to mention overwhelming. You can find a pack specific to just about every outdoor activity and in just about any capacity. So how do you narrow this impossibly broad field to the exact one that will suit you?
First tip: don’t start with a pack and try to fit your gear into it. Start with the pile of gear that you need to carry, and select the appropriate model to carry that gear. So, if you will be traveling with skis, look for one with a ski carry. If you will be taking ice tools, make sure they can attach to the outside of your pack with ease. And if you plan to carry your pack on a long distance hike, make sure the weight, suspension, and capacity is suited to what you need to bring with you.
Most people dedicated to the outdoors own more than one pack, especially if they participate in different sports. Most commonly, people own 3 different capacities that cover a full range of load carrying: a 60+ liter pack for multi-day trips in the backcountry, a 35-40 liter pack for most gear intensive in-a-day missions, and a 20 liter or less pack for half-day adventures, side hikes, or carrying on routes.