I don't know about this situation because I wasn't there (although the amount of snow seems a little bit much). I can assure you however that spraying hot liquid on DRY POWDER snow below -10 degrees is worse than leaving it be. Take a broom to it, or in a quick turn just a tactile inspection is all you need. I have 40 Canadian winters under my belt, 20 of them as a pilot...trust me.