More than 30 years ago, Kate Bush became the airy godmother of earnest and challenging piano pop, softening the ground for the likes of Tori Amos, Fiona Apple, and a veritable Lilith Fair of like-minded female artists. In recent years, Bush has contented herself with raising her son (her last album was 2005's Aerial, which at the time was her first new album in a dozen years). She's in jazzy and expansive Joni Mitchell mode on 50 Words for Snow, incorporating elements of pop history while occasionally venturing beyond it. Aggressively ambient textures fuel the longer tracks (like the 13-minute "Misty"); familiar but edgy pop defines the shorter ones (like "Wild Man" and the torchy "Among Angels"). All of the songs — which are inspired by falling snow — reflect Bush's deepening vocal range and musical maturation. — Brian Baker