A frosty Friday

This time of year, we sometimes see hoarfrost in the mornings. Hoar in Old English meant “old” – a sense which still survives in the phrase “a hoary old joke”. From meaning “old”, hoar came to mean “grey-haired from age” and then simply “greyish-white”. The frost that forms on trees looked to the Anglo-Saxons like white hair on the head, so they called it “hoarfrost”.
I was talking about this word to some friends and was quite surprised to learn that they thought it was a fairly obscure word that they themselves wouldn't use. Perhaps this is because hoarfrost is not a very frequent meteorological phenomenon in Toronto. I didn't ask them what word they would use when it does happen. But I'm curious: is "hoarfrost" part of your active vocabulary? If not, what would you call the white frosty stuff that forms on trees and grass? Let me know in the new, improved, easy-to-use (I hope) comment field.
See also the results of my inquiry into the declining popularity of this word in my post "Hoarfrost in a downward spiral".