My old Mountain Hardware Polarguard Delta -20 F. bag is really only good to about -10 unless I wear long johns to bed.
BUT... it has a side gore zipper above the opening zipper that opens it up another 4 or 5 inches. I can insert my WM Megalite bag inside W/O it being compressed much at all. So far I haven't needed to do it. That "down inside/synthetic outside" system will let vapor condense in the synthetic bag.

That is my "Below -20" system, with a regular RidgeRest mattress beneath a Thermarest Trail Pro. Plus I always put my zipped up GTX mountain parka over the foot & leg area of the bag in winter camping. Keeps frost on the tent walls from being melted by the bag's foot box.

What, if any, is your extreme cold sleep system?

Wow, you carry a synthetic -20°F bag? I don't even like carrying my 0°F synthetic bag.

The system I'd like to try this winter is my 0°F cuben fiber down quilt inside of my Golite 20°F quilt. The drafts will be miserable, but that's all I'm willing to carry. I may build a big breathable 0°F down quilt this winter, and combine that with the Golite quilt for colder temperatures.

Hi Eric,

For those temps I would be packing an Exped DM 9 and a PHD Hispar 800 Down bag.

Cheers,

My extreme cold sleep system is the same as my 'normal' winter sleep system.


Downmat 7
Montbell UL SS Down Hugger 0


I add:
Down Pants
Down parka
Snow shelter (quinzie or trench).

I've used this system to sleep just fine (actually was a bit warm) down to -40 F.

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Edited by rOg_w on 05/28/2012 17:17:20 MDT.

Chad, your setup seems to be what I will use but only down to 0 F. B/C I'm starting with a bag good for only 20 F.

i.e. my WM Megalite (now overfilled by WM) EB Down Sweater and Theromlite Micro insulated pants.

I "need" some WM down pants and will likely get some this winter. Synthetics are bulky to pack, even for a pulk setup.

BTW, I think I'll try a VBL suit. Week long trips without a VBL make down bags wet. Don't ask...

Oh yeah Eugene, about that -20 F. bag weight - it truly is d@mn heavy and when in a compression stuff sack STILL has to be strapped outside to the bottom of my big Dana Terraplane because it won't fit inside the zippered sleeping bag compartment. Only my Polarguard 0 F. bag fits inside.

Edited by Danepacker on 01/05/2012 19:31:37 MST.

This is a timely post Eric.

Last year , I used this system down to -14F

ground cloth - tyvek
two 1/2 foam pads
-30 MH Lamina
base clothing (smartwool - wind layer)
"fat suit" ECWCS Gen III layer 7 top and bottoms
three hats - skull cap-fleece-fleece
shelter golite SL-3


This years mods:

Ground cloth - reflective emergency blanket
1/2 foam plus exped-7
-30 MH Lamina
same base and fat suit
3 hats - skull - fleece-wool
10 x 10 tarp

Possibilities:

Sacrifical over quilt - link:
http://www.weberarctic.com/arctic-gear/polar-sleeping-bags
- this may be a future MYOG based on the above

Dave

Edited by dmgoody on 01/05/2012 20:56:55 MST.

Yeah Eric for a normal winter where I backpack the night time temps are around 5F so I like to have a bit of a cushion for those odd nights out where low lying areas or cold air following a river drop things down even lower.

Of course this winter season is incredibly warm (yesterday was 55F, record high)so I move between my 0F and 30F depending on the weekend.

Down to around -15F:

Bag: WM Kodiak (long)
Pad: Exped 7 DM
Down Sweater: FA Downlight
Belay parka: FA Mountain Guide Hooded Jacket
FF: Volant Pant

If I do expect -20F and then I will take my FF Peregrine and the Exped 9 DM. For Christmas however my wife purchased me a WM Puma (I handed down the Peregrine to my wife) and that is what I will be taking to McKinley in May and Chimborazo later in July.

If it makes a difference then I always use this in either a singled walled BD Eldorado or my doubled walled, 10 year old Wild Country Quasar.