As the guy said....adhering is the key word and if it is well below freezing and the wing is also well below freezing the stuff is not adhering than go.....
"It was more than my opinion that morning that the loose powdery snow would have departed almost immediately during the takeoff roll;"
How can you know this until you start the takeoff roll. And then, if it doesn't blow off?
If it is on the wing isn't it, by definition, adhering?