Oh, To Sleep on Denali (Sleeping bags etc.)

Post by WildSnow.com blogger | June 19, 2010      

While stranded here on Kahiltna Glacier like an icebound passenger ship, to break the boredom I’m getting going with more gear blogging. That’s good, because other more dangerous options exist. Outside my tent door the boys are building a terrain park, and the folks doing the Kahiltna Stare are still standing and gazing into the fog like patients in a mental institution. One can only assume they’ve gotten into their medical kits.

Today I got inspired to mention a few things about our tent gear.

Tyler with his Feathered Friends rental sleeping bag. Good choice, he says he slept in his skivvys even at 20 below zero. For exact model contact Feathered Friends and explain your needs.

Tyler with his Feathered Friends rental sleeping bag. Good choice, he says he slept in his skivvys even at 20 below zero. For exact model contact Feathered Friends and explain your needs.

As you all know by now from multiple blog posts, we’ve been very happy with our Hilleberg tents. Moving on from that, for ground insulation Louie and I got a 1/8 inch foam tent floor cover from Forty Below, and use Exped Downmat 7 Pump sleeping pads on top of that. The other fellows have similar combos, with or without the tent floor cover, using layers of foam pads and Thermarest inflatables.

The main thing with whatever pad system you pick is that you evaluate the weight vs other systems. For example, if you go with a tent floor cover, you don’t want to overdo it on the rest of your pad thickness and end up carrying more than you need. I sleep cold, and still found the Exped 7 to be plenty warm on top of our covered tent floor. Indeed, if I were to head up here again I think I’d try a slightly thinner and lighter inflatable, and still use the tent floor cover.

Regarding inflatables, the Exped Pump sleeping pad does have a built-in hand pump that works better than the first impression you get. Nonetheless, we highly recommend an airbag inflation system that doubles as a larger stuffsack — much less work.

Louie and Lou's tent in real life, Expeds and Forty Below on the floor, Louie catching a snooze.

Louie and Lou's tent in real life, Expeds and Fourty Below on the floor, Louie catching a snooze.

The beauty of the Forty Below floor cover is multi faceted. Mainly, once the sun hits your tent you end up quite a bit warmer (sometimes too warm) because you’re insulated from the ice block underneath. Another nice thing is that you don’t have the clammy condensation covered nylon that you have with a regular tent floor. You can throw gear around anywhere and it stays drier, and if you have electronic stuff the foam floor is a much better (drier and warmer) place for such things than setting them on a thin sheet of nylon over ice. The Fourty Below tent floor is white, which makes it much easier to find small items of gear in dim light than it would be on our black tent floor.

As for our Exped Downmat 7 pads. These things really are impressive and highly recommended, though again, if you sleep warm and use a tent floor cover, you should try something a bit more minimalist and see if it works so you’re not carrying extra weight. But if in doubt just bring something like the Exped.

A bit about sleeping bags. While I’m still a fan of synthetic, and can honestly say that some of the modern synthetics are nearly the same warmth as down per unit weight, it’s true that synthetics are more difficult to pack and in a warm/thick bag you do start to incur a noticeable weight penalty over down (at least when the down is fresh and dry, not after it’s absorbed moisture during sleeping).

It turns out that during a normal Denali expedition, you get enough solar heating in your tent to keep a down bag dry. That is unless you spend a lot of time camping high and receive more than your share of storms (and possibly end up in a snow cave or igloo). In that case, you might begin to see your down bag start to loose loft due to moisture retention and lack of drying time. That said, the vast majority of climbers up here do use modern down bags, sometimes with vapor barrier liners, and everyone seems to do ok.

So, what sleeping bags in particular? Louie and I are both using The North Face Climashield bags (Tundra model), mine with a down liner bag which I customized to tie in with a bunch of small sewn-in tabs. The Tundra bags are rated by North Face to 20 below zero F, but we found that to be optimistic. After a few 15 to 20 below zero nights up at 14,200 feet here on Denali, I’d give the Tundra more of a 10 degree above zero rating for my cold sleeping cuerpo, and a zero or 5 below rating for Louie, who sleeps warm. To remain comfortable at 15 below, we zipped our North Face Himalayan expedition parkas together into a quilt and threw that over us, which worked nicely.

As for the other guys, we’ve got a few sleeping in Marmot down bags, and a few in Feathered Friends models. Of any bag out there, it’s my feeling that the Feathered Friends over-deliver in warmth and performance, and getting set up with one for Denali would be a very good idea if you’re uncertain about what to bring. The company rents their sleeping bags, so that’s a good option if you don’t need to invest in a sub-zero down bag (the Feathered Friends bags we have on this trip are rentals, and they’re working fine).

Some sleeping bag tips: Many models have a complex system of Velcro and drawstrings to operate the hood, zipper closure and draft collar. I you tend not to use a draft collar, just cut the dang thing out or at least cut the velcro off. Otherwise, practice using this stuff at home. I don’t use a draft collar and found the collar velcro kept sticking to other stuff while I was sleeping, including my hat. Nothing like being half asleep and feeling your head stuck to your sleeping bag. After that fine experience, the draft collar velcro was removed with my swiss knife sissors and I’m now a much happier camper.

One advantage of synthetic bags is that if you tend to a dry throat after sleeping (I do), you can just throw the hood over your head and re-breath your warm moist air. Doing so with a down bag is not a good idea, as the down around your head will become quite saturated with moisture and be difficult to dry. With this in mind, if you tend to not use your sleeping bag hood in the conventional sense, consider covering any velcro hook you don’t use with a chunk of fuzzy velcro, that way you won’t have the danged stuff grabbing your hat all night, or even your socks as you exit the bag.

Sleeping bag ratings are always a laugh. You wonder, are they rated for what minimum temp you could survive in? Or are they rated for where you’ll sleep comfortable? And what about the incredibly wide range of folk’s metabolisms? My advice for Denali sleeping bag selection would be to first know your sleeping metabolism. Most outdoors people know if they sleep warm or cold compared to other folks, so just keep that in mind as you configure your system, and don’t get too optimistic. Your metabolism can only produce so much heat at high altitude, and sleeping warm and comfy is key to staying strong while doing any sort of alpinism.

I’m certain many of you winter camping vets out there have something to add or disagree with. Please comment and share your wisdom.


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9 Responses to “Oh, To Sleep on Denali (Sleeping bags etc.)”

  1. Ryan June 22nd, 2010 3:11 pm

    As a rep for Marmot bags I’m glad to hear they weren’t the bags that inspired the most feedback from you. I am curious as to who uses velcro near the face? I can’t imagine Feathered Friends doing that either as they may a top notch bag for sure.

    Also while I agree with some potential for discomfort with poorly designed draft collars they do factor in with a bags temp rating so cutting them out will hurt the bags rating and negatively offset any weight gains by doing so.

    I’m also a fan of some sort of insulated floor of sorts for any winter type scenario where you’ll be living in it for awhile. I do like the idea of it being white though. That would make life easier.

    Thanks for all the info and safe travels to you and your crew.

    Ryan 🙂

  2. Jordan June 22nd, 2010 3:22 pm

    The 3 of us that used th cwm bags had absolutely no complaints on them at all…save for maybe being too warm 🙂


  3. Lou June 22nd, 2010 7:17 pm

    Ryan, I was speaking mostly from my own experience, and used the TNF bag as well as dealing with Feathered Friends to get their rental bags. I think the velcro issue for me was caused more by my style of sleeping, but any bag with velcro in the head/shoulder area should probably have some way of covering up the hook side. I find the draft collars to be too claustrophobic and confining, and don’t feel they add very much warmth if the hood is used. If the hood isn’t used, the collar does add quite a bit of warmth. As for the Marmot bags, as Jordan says they worked well.

  4. Mike Bannister November 4th, 2011 9:57 am

    Lou et al,

    What seems to be a more effective sleeping bag shell up on the glacier: G***-tex to get the down dry from condensation etc, or nylon/micro-fiber to help the bag breath and not get soaked from perspiration? Or plain nylon with a bivy sack? Both schools of thought seem to share quite a few advocates. Also, while I’ve slept in my current bag with my boot liners to dry them, its rather tight and unpleasant. Did you guys get extra long bags for liner drying or just do the ski boot snuggle? Thanks!


  5. Lou November 4th, 2011 10:05 am

    Mike, I think it depends a lot on your type of shelter. If you’re using a roomy tent, you’ll have less of a problem with shaking frost down on your bag after a night’s sleep. Also, if you’re using synthetic bag (which I still recommend though down does work when properly cared for) I wouldn’t worry about it.

    Down or synthetic, my method would still be to use a bag with plain nylon shell so it breaths and is easier to dry out in the wind/sun. Along with that, I’d still carry a super lightweight bivy sack made with one of the more breathable semi-waterproof membrains, such as Windstopper. Hard to find those. I usually make my own.

    Most people on Denali get away with fairly random combos of sleeping gear, since everything is so good these days. Where it hits the fan is if you choose to camp up at 17,000. That’s a whole different world than 14,000.

    With my age and skinny body, I sleep cold. My combination of synthetic outer bag and down inner worked really well on Denali. I did sew a bunch of attachment points to keep the down bag from getting all twisted up.

  6. Brent December 5th, 2013 8:36 am


    I’m curious how you used the Forty Below tent floor. The floor foam is 40″ wide according to their website, and the Nammatj is 52″ wide. In the photos it looks like you have wall to wall coverage. Did you piece two floors together to fit? I recently purchased a Nammatj, and like the idea of using a floor vs multiple pads.


  7. Lou Dawson December 5th, 2013 9:03 am

    Hi Brent, yep, we got a bunch of the foam and just taped it together with Gorilla Tape. Worked super well. Leave a little space under the tape and you’ve got a hinge for folding up the floor. I thought the tent floors made a huge difference in comfort. Ours was especially appreciated when my modified air pad sprung a leak at the 14,000 foot camp. I’ll admit that scared me. Small things have big consequences on Denali.

  8. Brent December 5th, 2013 9:08 am


    Thanks for the quick reply! I’m tempted to do the same with the floor. We spend our time below below 14k, mostly in Colorado and New Mexico, but this would eliminate the ridge rests we use under our inflatables now. Great blog, btw!


  9. Jared March 22nd, 2014 10:32 pm

    hey Lou, what did you use for a down liner for your sleeping bag?

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