If you watch the video, you'll clearly see at the end of the wing, some snow mechanically brushed off.
No sir, what you probably see is the warm fuel in the outer tank melting the snow sitting on top of that tank. In the 320 fuel is circulated to cool the generators. The surplus of this fuel is returned to the outer tank. Or it might simply be fuel that was already much warmer than OAT when it was uplifted, again, melting the snow sitting on top of the tank. Whatever it is, ice melting on top of the fuel tanks is a sight very well known to any busdriver.
Green guard, nice googling, but what is the Inuit word for 'snow sitting on top of the wing being melted by the IDG-cooling fuel'?
Warmkitter below, excellent post, but may I point out that the wing was NOT clean on liftoff. There was still some snow and lots of ice, you can see bits of it fly off after liftoff.
