Currently, I’m working on MISTWALKER (which will come out Fall 2013 from Houghton, whee!) and I’ve discovered a fundamental difficulty. There are only so many ways one can describe fog.
On the upside, I’m halfway through the book so I probably only need to figure out about 100 more ways, but wow. Lesson learned, self: no more monochromatic themes in fiction!
Some lovely fog from my back door, taken a couple years ago. When it was foggy. As opposed to today, when it’s SNOWY. Oh hai, all winter in a day!

OMG, this happened to me when I was writing a book that took place in the winter and everything had to do with snow/ice (LOL).