An Event bivy will never condensate on the inside. FirstLight tents are great, unless your over 6'0" then you need the LightHouse which is more like 4 lbs. My bivy weighs less than 2 lbs, plus its easier to set up than any tent. I used to have an Integral Designs Uni-Shelter which was great other than having to stake it out and insert the "tent pole"... (the South Col still had about the same headroom as the South Col).

I suspect that the still, nearly windless conditions may have contributed to the condensation. I could see frost forming on the fabric's surface as the sun dipped behind the ridge.

I had similar condensation issues with my old goretex bivy in humid conditions. That south col eVent bivy is starting to look pretty good .. what kind of trips have you used it on, and how has it performed ?

I usually don't snowcamp with a bivy .. I typically just use them for alpine trips where I don't want to lug a tent or pitch a tarp, mostly for protection from wind and "possible but unlikely" rain (ie. Sierra late spring/summer/early fall)

Howdy Rob. I've used it most recently in the local mountains in San Gorgonio, I slept in a snow cave. It was a clear, warm night, lots of frost. Kept my 40 degree bag dry and it seemed to boost the insulation value of my bag by about 10 degrees, never clammy. A couple weeks ago, Blair and I spent about a week bivouacking dirtbag style in the Alabama Hills, a few windy nights, no problem with the wind getting through either. The cut is pretty roomy, its not even their biggest bivy. The Bugaboo has a couple inches on it girth-wise however the center zipper seems silly to me... Am I crazy? Anyways, the South Col has plenty of room for me to toss and turn and I'm a huge beast of a man.

Cool, thanks Steve. I'm going to give this eVent stuff a try.

re: zippers -- the other annoying thing about the spotlight is that it has a right-handed zipper while my sleeping bags are all left-handed.

I have a Lightsabre Bivy and have lots of experience with a Firstlight and Hilight, as well. The Lightsabre is fine so long as it doesn't snow, at which point the leg section gets matted down on your bag and condensation gets bad. You can bring your boots inside the bivy but have to dig out your pack in the morning. The Firstlight is the ideal way to solo camp in winter conditions, IMHO. Just be warned that either due to freezing condensation or EPIC's breathability I have seen it snowing inside the tent with everything zipped up when the weather outside is wild. Snow walls should be sufficient to solve that, but they're hard to tend to when the wind and snow is pounding. Anyway, for solo winter camping when the weather is lousy, nothing beats having all of your clothes, gear and boots in your 'bivy' that weighs under 3 pounds. Otherwise, if the weather is fine, the Lightsabre treats me well and packs insanely small. I have no connection to BD despite my obsession with their products.

FWIW, the Spotlight is the thin wall equivalent of the Bibler Bipod and the Lightsabre was equiv to the Tripod (two poles at the head, one at the foot). You're stuck with the bad leg condensation either way but the Lightsabre has been good for me when left sufficiently ventilated in lousy conditions. That might be tough with the smaller tent area around your head and chest with the Bipod based version.