by Matt Peck » Tue Apr 26, 2011 9:45 am
Hey Adam.
So I always go with Synthetic between 10 and -10 degrees, as I find this is the range where you're most likely to perspire/encounter damp conditions and have problems with this later. Down is ok if you are doing 1-2 days out, but for longer you are gonna stay cold if it get's damp. Not sure if you're doing bigwall or anything, but if so, there's always the chance that you're going to drop something or get caught in a flash storm where you get soaked/stranded on the wall. In those conditions only a synthetic is going to keep you alive (not necessarily comfortable, but alive). I had the chance to demo a Western Mountaneering bag a couple of years ago in North Conway, and I was amazed at how light it was and still warm. It's basically a sleeping bag version of MEC's amazing Uplink Jacket. It was so light that I didn't feel that I should be as warm as it was. Kind of like staying toasty in the winter while only wearing a linen sheet, psychologically, you feel like you need to be wrapped in a duvet to be warm.
MEC's bags are also really good, and a much nicer price (WM bags are big $$$), but no contest when it comes to bulk/weight/proformance.
You could also consider a fleece bag liner combined with a bivysac, but that might be overkill.
The big thing that's gonna keep you warm is a toque, and always changing into a dry layer before sleep. Otherwise you'll spend hours drying out the day's exertion moisture before you dry out, even if it's only slightly damp, and all that moisture will wick into your bag and haunt you later.
Some food for thought I guess.
You can't take the sky from me.