Heather
A friend of mine brought a pair of those boots along on a winter trip to the Sierras. I was wearing my ancient Sorels. After a while of sitting up in the moonlight he says \, "My feet are cold and I'm wearing -60 boots, they don't work!!!!!"

I asked him what he was wearing on his legs and he had some lightweight insulated pants on. I told him that I had brought a spare pair of real down pants for him to wear and to try them on. Ten minutes later his feet were toasty warm.

The moral of the story is - It doesn't matter how well your feet are insulated if the blood arrivibg there has cooled down already - to keep your feet warm - insulate your legs. If you are properly insulated in the winter your face will glow because it will be the only spot that radiate heat well and if you take off your glove your hands will steam.
Jim