Some years ago in FRA, queuing for rwy 18 in freezing conditions, we noticed the aircraft in front of us appeared to be accumulating a heavy layer of ice on the trailing edge of the inner portion of the wing. There was no doubt the aircraft had been de-iced as the foam was visible dripping in several places. We surmised that the ice was forming due to the light snow falling at the time being melted in the jet exhaust and then settling on the cold wings. The tailwind as we taxiied down to 18 was about 15-20 knots, enough to send the exhaust gas back over the wing.
We advised the crew of the situation only to be told they were happy as they had been de-iced and had another 10 mins of hold-over time. We watched as they took off but lost sight of him about 1500m down the runway in the driven snow. We feared the worst and said so to each other, sure that we would see a fireball in the gloom.
My FO flicked over to the departure frequency and heard them call in, much to his relief, but then concern when ATC asked him to verify his altitude was 200 feet! My guess is that he should have been around 1000' at that point.
We returned to the ramp and had the half inch of solid ice removed from the rear half of our wing. It stopped snowing soon afterwards.