(2) What about the slushy, icy snow that builds up on your car's mudguards in the winter, and makes scraping noises on your tires when you make a sharp turn? You have to kick it off with your boots. What is the word for it???

(I'm hoping the red font will help you feel warmer...)

Last winter, a Minneapolis columnist had something of a contest to come up with a name for just that phenomenon, and I really liked the winner... I continue to use the term because it was so satisfyingly onomatopoetic. Great Grungy Underwhomps.

Great, naturally, because they have a tendency to grow to epic proportions before you know it.
Grungy because they're never pristine white snow, they're always utterly filthy.
Underwhomps because A: they accumulate under (and behind) the wheel well, and B: the sound they make when you kick them off.

That coinage did it for me! I'll see if the article is still in his archives. If I can find the link, I'll post it here...