I am cabin crew for a British flag carrier which operates to Moscow.
Years ago I called the flight crew because I was concerned that we hadn't been de-iced and there was a large volume of snow on the wings of our 767. I was told that it had been discussed between them, the wings had been inspected by the ground engineer and it had been decided that due to the intense cold (minus 20) the snow hadn't adhered to the wings and that they were completely clean underneath.
We started the takeoff roll and as predicted, the snow shot off the wings and left them clean at about 50 knots.
Quite possibly the exact same circumstances at in the original video.