"Lightweight techniques apply to winter, too!" they say.

OK, sure. But with a very serious disclaimer.

You better know what you’re doing.

Send someone out in the wilderness with an extra hat and a warmer jacket in combo with your summer kit and they could be in for a rude awakening.

First, read Last Breath, and in particular, the chapter about dying of hypothermia. That, at least, sets the scene for your final moments.

What leads up to those final moments?

For the unseasoned expeditioner venturing into winter for their first experiences, the greatest challenge is condensation management. You can’t appreciate the difficulty of this on an overnighter, or even a weekender. Spending a week or more sleeping in subzero (Fahrenheit) conditions is truly, a whole ‘nother ballgame.

A vapor barrier strategy is essential for expeditions at these temperatures. Otherwise, your sleep system will fail. You won’t have the chance to dry it out, you won’t have enough insulation to provide a buffer against loft degradation, and you won’t have the fortitude to deal with the reality if you’re hunkered down in your grave in the middle of Alaska or Montana or Nepal come December 31.

Happy new year.

Commercially available vapor barrier liners are a total joke, if not at least a moderate inconvenience: the lightest ones suitable for expedition use (read: durable) on the market weigh 5-8 ounces in silnylon or mylar-coated nylon, and don’t allow you to synergize your clothing system with your sleep sytem. VB liners and long underwear buy you only a few degrees while you sleep atop a puffy pillow of down jackets etc.

So why don’t more manufacturers offer VB clothing? Stephenson’s has it, and it’s good stuff, too, but it lacks style and then there’s the thing with the naked people from 30 years ago.

RBH Designs offers more promise, but at 10 oz, the prototype jacket I’m using still can’t be considered ultralight and no matter how I spin it, I can’t figure out how it buys me more warmth than an extra 10 ounces of down. I guess I’ll find out on my SUL Winter Challenge…

Hal Weiss has it right, and others are investing real thought into it, but the market has been extremely slow to adopt the VB concept.

But hopefully, like IPOD Nanos and chlorine dioxde, the "a ha" will be realized among those of us (and the manufacturers that make our gear) that like to go cold, but go light, too.