Pete,

If the QLD in your name means you're from Queensland, get some cold weather clothing, otherwise you will probably freeze your butt off in Idaho. It might be a good idea as well to obtain cold weather clothing once you are in the USA because the "winter clothing" I've seen in shops in Australia is not made for the types of temperatures you may encounter.

Also don't forget a good pair of sunglasses, because if it snows when you are there and the sun comes out, the glare off of the snow can hurt your eyes and make it difficult to see.

Richard.