Layering Two Summer Sleeping Bags For Winter?

[powderhound]

I currently have a WM Ultralite 20F bag, and am considering buying a 30F Marmot Hydrogen for warmer conditions and to have more wiggle room. However, I'm also getting into mountaineering and am wondering if I could possibly layer these two bags in the snow to avoid having to buy a winter-specific bag (a $500 is bag is out of the question at the moment). Would this work, or would the bags compress too much? I'm looking at some High Sierra adventures, some rocky mountain trips, and also Mt. Rainier in the not so distant future.

[psykokid]

Should work just fine. I've used this trick with my kids in the past. Only thing to note is that your outer bag should be cut a bit bigger than your inner bag as to not compress the down too much.

[paul]

If you just use the outer bag like a quilt then no issues due to compression of the inner bag. I made a synthetic overquilt for my Hydrogen for snow camping and it works well.

[limpingcrab]

I just use a thin liner in my summer bag and put a hand warmer in each sock before going to sleep and it's worked well for splitboard trips when I didn't even have a tent.

As mentioned above, I think using one as a blanket and getting inside the other would be warmer unless your outer bag is considerably bigger.

[Tom_H]

I did a trip over the top of Roan Mountain NC once in the winter of 77-78 using a pair of 3 season bags. They were either PolarGuard or Hollow-Fill. In my case, there was too much compression and the fill did not loft as it should have. It was also difficult to get the two nose holes completely drawn down and in alignment. I went to bed the first night mildly hypothermic, knowing my socks were slightly damp, but didn't bother to change them. The bag-in-a-bag didn't work effectively for me due to the reasons above. A super cold front came through and the temp. dropped to negative 40. I got mild frostbite in the nerves of the soles of my feet, and had to hike on snow or ice for four more days in a lot of pain. For a full year, every time I got out of bed and first set foot on the floor in the morning, it felt like jolts of electricity bursting through the bottoms of my feet.

Others seem to have had better success than I did, but my personal recommendation would be to avoid this method. And Mav is correct below about the unnecessary extra weight & volume.

[maverick]

If you are seriously considering mountaineering, then you have to think about not only temps, but the weight too, two bags are going to weight a lot more than a good quality mountaineering bag, plus getting two bags into your pack is not that easy, when you already have a bunch of climbing gear and winter clothing in it already.

[CAMERONM]

Yes, it works, keeping the previous comments in mind. If you wear a down jacket, pants and booties to bed, that takes you most of the way there too. Of course, up your game with the sleeping pad as well.