Cool video

[frnash]

doo_dr-

That is called rime ice. It forms when a cloud containing water vapor comes into contact with an object that is below freezing. Instead of dew forming, you have ice. Same thing happens in the mountains to trees near the higher peaks all the time.

Not nice when it forms on the leading edge of your airplane wing either! It doesn't make a very aerodynamic surface, and can thus have a serious impact on lift. Not to mention the added weight. Of course flying through clouds of any variety should occur only on an IFR (Instrument Flight Rules) flight.