Use Inov8 Oroc 280s for snow/icy conditions and there superb, if its more snow than ice X-Talon 212/mudclaws are a very close 2nd place..
In the past I`ve used your avg trail shoes but there performance is quite limited compared to the shoes mentioned above.. 6-7min/mile pace is easy with orocs along snow/icy roads leading to the forests..
Strange as it might sound Tracey but snow gives much better grip than mud so slapping on a pair of fell shoes and you`l be able to run as fast as you like without slipping.. Orienteering shoes have little metal dob spikes and they give fab grip on snow/icy surfaces.. Inov8 Oroc 280s let me run along this road at 20min 5k pace!!
Having alot of support/cushioning in a trail shoe actually works against you, if your trails get rough during the winter your increasing the risk of ankle problems..
A flexible sole also helps becasue it`ll twist/deform if your foot strikes a big stone, edge of a rain rut or an exposed tree root, given the same situation a stiff sole will remain rigid so the shoe will twist and your ankle takes all the abuse..