Have you tried on POW gloves before? I've noticed they seem to run a little small so I've had to bump up a size on my POW gloves/mittens over what I'd usually get with a Dakine/Burton/Drop glove.
15 LibTech TRS HP . 15 NS Snowtrooper . 15 NS Ripsaw . 13 Salomon Pow Snake
15 Now Drive . 14 Now Drive
14 Flow Hylite