Powder skirts on snowboarding jackets are designed to help keep the snow out of the waist area of your jacket, so if you fall or slide, you won’t get snow inside the interior of your jacket or pants. Powder skirts won’t always keep out every ounce of snow you might encounter, but they do help to repel snow and keep it out of the interior of your outfit. If you want to make sure you probably won’t get snow in uncomfortable areas as you snowboard, then getting a jacket with a powder skirt is an effective idea.