As the name suggests Powder boards are designed to deliver maximum performance in deep snow. This means that they are generally fully directional with a larger and wider nose profile than tail. This allows the board to float in deep snow whilst the riders binding position is set back on the board to help keep the nose up and reduce fatigue.
Powder boards (with a few exceptions) due to their extreme shape and design are generally compromised when riding anything other than powder so are normally bought as a second board. Their performance in deep snow is so much better than a normal board and delivers one of the sports best ever sensations, so they are becoming more and more popular. As float is the key in powder boards it is most common for them to feature some form of directional rocker or other kind of profile shaping to help get the nose up.