Earthling
Goretex is teflon foam. sort of.

Thats why I question that water vapor molecules can "freeze" inside of pores too small for water molecules. <img src="/forums/images/graemlins/confused.gif" alt="" />

We used a megamid in a windy snowstorm. Spindrift aside, the condensation was so bad (because the moist air freezing high in the tent) that it snowed inside the tent as the frost broke off. Without bivy bags our sleeping bags would have been covered with frost. <img src="/forums/images/graemlins/confused.gif" alt="" />

Trailrunner,
don't misunderstand me, and my rejection of Dr Jordans idea. I worked in a large lab with 1/3 doctors on the staff. As you mentioned about the forum, if we only used science that all the doctors agreed on, there wouldn't be much. I was a principle engineer with teams working for me. I respected all the doctors, but I was responsible for shaping what they designed so all the pieces fit together. The more ya know, the more ya question. I look for chaos, others look for simplicity. <img src="/forums/images/graemlins/laugh.gif" alt="" />

I do believe that woven "breathable"fabrics that depend on fabric pores can freeze up.

Jim <img src="/forums/images/graemlins/cool.gif" alt="" />