Does the Mentor have a powder skirt?
No the OR Mentor Jacket is a lightweight shell made for climbing and aerobic activities. Look in the ski jacket product group for jackets with powder skirts.
I am actually looking for something to use for both backcountry snowboarding and winter mountaineering. An optional powder skirt (zip out) is something I have found in other similar jackets I am looking at, like the Marmot Alpinist and Arcteryx Stinger. The Mentor is a less expensive Gore-tex Pro option. It looks like a lot of people here have purchased it with skiing in mind. That looks promising...