Unless you are a very good skier (and never fall) then I wouldn't use them. I know some of the Cross Country ski racers use carbon fiber poles, but my guess is that the poles are thicker and the skiers are much better than us (and traveling on groomed terrain). I've broken trekking poles while snowshoeing. It is very easy to sink a pole into deep snow and then put pressure right in the middle (where it is weak).
Joe is also right about the length. Black Diamond makes a lot of very good adjustable poles that work well for Nordic skiing. One of the really nice things about the Black Diamond poles is that they stay locked (which reduces the chance of breakage). I would get the ones designed for winter if you go with Black Diamond. I saw a friend break a pair of Black Diamond hiking poles while crossing a creek, so I could easily see how that could happen while playing in the snow.