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jim23
Jan 19, 2008, 11:33 PM
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Registered: Jun 13, 2006
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given that different people have varying metabolisms, that proper acclimatization, hydration, is important at altitude, etc... Given that all of the typical guidelines are followed for cold weather sleeping:
have any of you had experience using higher temperature-rated synthetic bags in alaska (or in cold winter mountaineering elsewhere) when wearing to bed your insulated clothing+parka+primaloft booties, etc? I have heard peeps using bags as low as 20 degrees F on Denali, but thinking I may go with a 0 degree F bag to cover my butt. All of my insulation and bags are synthetic-filled. I'm waiting for a good cold snap in the Whites to try out my system before using it in Alaska this May. Basically I am looking to save a few pounds (and I am avoiding using my down bags because of moisture concerns).
Just throwing this out there out of curiosity to hear what your experience has been.
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kimgraves
Jan 20, 2008, 12:04 AM
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I've used my 10 degree bag on Mt Washington in -10 wearing base layers, mid layers, belay jacket, belay pants, booties, hat and was VERY comfortable. Also had a BD Winter Bivi. Would feel confident I could go to -20 or lower. Be sure to have enough calories and pee when you need to (don't hold it).
Kim
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james481
Jan 20, 2008, 2:07 AM
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Well, I've never been to Alaska (sadly), but in my experience, if you can spare the weight and bulk, it's far preferable to carry a bag that will keep you warm without wearing all your layers (excepting mountain hardmen who will swear all you need is a sheet of waxed butcher paper to sleep under on the west buttress). I find that wearing all your layers to sleep, especially if you include layers with membranes (soft or hard shell) leaves you much more susceptible to overheating in your sleep and badly sweating out your insulation. If you do decide on a light bag / all clothes sleeping method, just be sure you go to bed nice and cold to make sure you don't wake up even colder in the middle of the night (not too fun, if you've never had the pleasure).
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michaelmcguinn
Jan 20, 2008, 3:42 AM
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I went to Denali and was very successful. I have about 100 days in the Alaska range.
I took a -40 bag and it was good. It does get cold there and I dont like wearing every thing I have to stay warm at night. Every now and then I tossed my jacket over the bag for more insulation.
A lesser bag to save a pound or two is insane. You will be taking a lot of other stuff and that will not matter.
Be comfortable. You could be in the tent for days. Resting or bad weather.
Each person I went with had the max 125 lbs of gear.
Synthetic is fine but down is lighter. You can also use a vapor barrier too.
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kricir
Jan 20, 2008, 4:03 AM
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I think It could depend on your strategy. The light bag / clothing combo would make sense for a fast alpine attack in a good weather window, but if your planing a longer, more traditional approach, hauling a couple extra pounds for a warm bag would probably make you happier in the long run. That being said I'v slept in -20 with a +20 bag, clothing (including a puffy coat) and hugging a nalgene full of boiling water and been warm.
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jeremy11
Jan 21, 2008, 8:25 PM
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these guys did (attempted) Denali in ultralight expedition style, bringing a total of 80 pounds of stuff each, full skin out weight - all gear, food, fuel, clothing weighted was about 80 pounds each - they used Golite Gusts plus sleds up to 11,000. they did no double carries, and each day sounded pretty easy. they turned around due to a long period of bad weather, sitting at the 17,000 camp, and said that ultralight gear was not a factor, they would have made that decision no matter what the gear.
anyway, even cutting weight wherever possible, they still brought -20 down bags. Here are the links, (I know you need to be a backpackinglight member, sorry - thus the summary)
http://www.backpackinglight.com/...ng_denali_light.html
http://www.backpackinglight.com/...ng_denali_light.html
personally, not having done Denali or similar, there are much faster ways to cut weight on an expedition - cut 5 pounds somewhere else, and bring the extra pound of sleeping bag to stay happy at night.
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summerprophet
Jan 21, 2008, 9:46 PM
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You seem to want it all, Lightweight, warm and synthetic.
Sadly you aren't going to find it.
I use a -25c rated full dryloft down bag, for winter mountaineering, but it is incredibly warm for the rating sleeps warmer than the Marmot Col.
You can get incredibly warm and light eiderdown bags if you have thousands of dollars to spend on a bag. And such alternatives do not exist in sythetic.
While synthetics do have their benefits, the come in short on weight and bulk. I wouldn't be overly concerned about condensation in Denali, as the moisture will turn to ice on your bag surface, rather than seep into the down. If your bag isn't waterproof, get an overbag.
Also, many varietys of bags sleep differently. The tighter the bag, the warmer you will sleep, unless claustrophobia sinks in and you don't sleep at all.
So my short answer is this, if you intend on Denali, go overkill on your boots, bag and first aid kit, cut corners on everthing else.
Incidently the coldest night I spend out was well below -45c. The water bottle in my bag froze, and my plastic boots (Old Kastingers) cracked.
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skiclimb
Jan 21, 2008, 10:28 PM
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As stated before a light bag say 0deg can work during limited windows on the upper mountain. However if you get stuck at 17-2 for any length of time it's gonna be hell. Suggest no less than a -20 deg bag..and you might have a few cold nights even then.
If you want to save weight down would be my suggestion.. with a vb liner and using care you shouldn't have much of a moisture problem.
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jim23
Jan 22, 2008, 4:20 AM
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Registered: Jun 13, 2006
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Thanks fellas- lots of insightful comments. I will certainly bring a warmer bag for the bulk of the trip, either my -20F Marmot down bag, or an overbag for my +20F synthetic bag- if one exists that will add sufficient warmth... I was mostly concerned with keeping my pack light for the integral West rib climb. Thanks again- lots of experience and helpful advice here in the forum =).
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