Pit zips (underarm vents) aren't just a nice-to-have—they're one of the most useful features on any snow jacket. When you're hiking to a backcountry line, bombing groomers on a warm spring day, or just working up a sweat, opening your pit zips lets you dump heat fast without unzipping your whole jacket and letting snow in.
They work so well because your underarms are a major sweat zone. Opening that area creates instant airflow right where you need it most. Plus, you can easily operate them one-handed while riding the lift or standing in line—just reach under your arm and pull the zipper.
If you're shopping for a resort or backcountry jacket, pit zips should be considered essential. Even on insulated jackets, they're critical for preventing that sweaty, overheated feeling when you're working hard. Just check that the zips are a decent length—short pit zips don't move nearly as much air as full-length ones.