U.L. Overbag?

Ali, I think Jonathan Boozer was selling a -15 FF bag a couple months ago on gear swap, I don't think he sold it. The price was excellent- I almost bought it even though I don't need it (I let Jonathan do all the impulse buying for me)
You might want to contact him. The weight would be far less then your bag and the over bag, and the price was about the same (maybe a little more).
I don't have any experience with Wiggy- but 40* might be a stretch (unless it has about 2" of loft by itself) and then you are still pushing the envelope.

That bag looks nice but it is a long and I am 5'3". Thanks for the info though!

fold it in half and then you will have a -40* bag.

I would imagine that a true ultralight overbag would be expensive. To be truly ultralight, the fill has to be made out of very high quality down. For an overbag, you need to wrap the bag around the inner bag. Thus, you need a lot of high quality down. I think this would cost a lot. A FF semi-rectangular is sort of like what you want (bigger than a normal bag). It weighs about three pounds and costs $400. It isn't designed to be an overbag, so the cut isn't right, but you get the idea. Of course, you can always sacrifice weight to save money, but I would be surprised if you didn't up carrying a fairly heavy bag (even with the best synthetic insulation).

If your existing bag is roomy enough, I would try and maximize the inner part by adding lots of fleece/wool (good warmth/bulk ratio) along with some synthetic dual purpose insulation (Cocoon type clothing). Perhaps it might make sense to go with a vapor barrier? Then again, maybe it makes the most sense to just rent a bag until you find one used or one sale.

-15 is chilly!
I have not used the Wiggys overbag, but would be skeptical of the 40 degree added warmth claim. As Ross mentioned, the design requirements for overbags necessitate a heavy item, and so most are at least 2lbs. They do work well when the temperatures never get above freezing and internal moisture is a concern with down bags. This is generally what they are for, and is why most are synthetic and many have waterproof shells (think of them as insulated bivy sacks).
If you really will be in -15 temperatures you might have many days where it does not get above freezing and a synthetic overbag may be a good policy against loft deflation in your down bag. However, paring you bag with a rectangular down bag or down overbag will be a lighter option and pack much easier.

Some options:
http://www.bigagnes.com/Products/Overbags
Their lightest is about 22oz and claims to add 25 degrees. It is also pricey and uses down, which defeats the purpose of an overbag IMO. Anyway, check out their offerings for a good selection.

Mountain Equipment Co-op also offers two, the Penguin and Emperor with the former being under $100. Both are heavy.
Integral Designs has the Andromeda, which is again heavy but uses good materials for the purpose.

There is also a very basic overbag made by Cocoon for $100. I have not found a listed weight, but its design suggests under two pounds (no fill on the bottom and no hood).

Lastly, if you are trying to boost bag warmth the easiest way is to use a very warm sleeping pad. A down air mattress (I do not recommend Exped, mine has had numerous leaks) can give you an extra 10 degrees. Also, add some down booties and a down jacket (or synthetic). So long as you have enough room in your bag, wearing insulated clothing really helps and makes getting out of your bag on a sub-zero morning MUCH nicer.

Good point about the sleeping pad, Michael. I forgot to mention that (even though it occurred to me). You want to get as warm a pad as possible (either a down filled inflatable or many layers of closed cell foam).

The big agnes cross mountain sounds good. Although it weighs 2lbs 3oz, combined with my bag it's still only 3 lbs 10oz which isn't terrible. It also has a sleeve for my pad which will be nice.

I have one important question of Alli. Alli, where exactly will you be attending your NOLS semester? This is relevant because, if it is in Alaska, you cannot take a down sleeping bag with you. It must be synthetic.

I have an I.D. Andromeda Overbag, which I usually pair with my I.D. North Twin for backpack hunting and also what little bush work I still do. It is not heavy, being only 2 lbs. and is extremely H20 resistant and warm for it's weight.

-15*, if you mean Farenheit is COLD and you NEED a real winter bag plus a GOOD pad(s) for this; I have considerable snow camping experience and this level of cold will KILL you, real damm fast, if you are not prepared.

I would try to find a good, used down bag, there was a Snow Lion here a couple days ago, that would be perfect for this trip AND would STILL last a long time with proper care. Scroll down the "For Sale" section and see if it's still available.

"I would try to find a good, used down bag, there was a Snow Lion here a couple days ago, that would be perfect for this trip AND would STILL last a long time with proper care."

Yup, if this is still available (I believe it is), Alli should definitely grab it but only IF her semester isn't in Alaska as down is a NO-NO for sleeping bags on NOLS Alaska semesters.

It would be the Rocky Mountain Semester from September to the first week of December, in Wyoming. Maybe I'm an idiot but I'm skeptical of it getting to even 0 degrees in the first week of Winter.

edit: On the gearlist I have, it doesn't say anything about down bags being forbidden, it just says synthetic is highly recommended.

I know one thing, if you really need a -15 degree bag, that's the one place you don't want to try to cut a corner. A mistake there, and you're miserable every night. Or worse.

Remember, if you are at altitude, the temps will be colder.

Low temps in Lander are sometime zero F.

Zero in Lander could mean -20F at 10,000 feet elevation.

Add a little wind, sleeping under a tarp, a damp bag from drying out clothes, a bit of exhaustion—-

BRRRR.

I think I would buy some fabric and fill and make one of
these to go over your bag.

http://www.backpackinglight.com/cgi-bin/backpackinglight/cocoon_ul_180_quilt.html

true, but with the plethora of clothes we have to bring I would assume if it got down to -15 I would be OK with a 0 degree bag. Maybe I'm full of crap, in fact it's pretty likely. If I get there and the gear I have isn't good enough I can rent a winter bag for $20. I just don't want to get stuck with a 6 pound monstrosity which is why I'm asking for advice.

That snow lion looks great but I have no idea when I'd ever need a -40 sleeping bag again. Plus I kind of like the idea of having a synthetic overbag as a means of wetness protection.

Again I don't want to sound like I'm ignoring anyone's advice. I just want the most economical solution.

Hi Alli

Listen very carefully to Dave O.
Or buy one.

Cheers

“Again I don’t want to sound like I’m ignoring anyone’s advice. I just want the most economical solution.”

Well, the most economical (and you’ll have an awesome bag) solution is to buy that -40 degree Snow Lion bag advertised over in the for sale forum. For $200 you can’t go wrong. Yes, it’s old, but it still has a lot of life left in her and comparable new bags, as you stated earlier, are well over $600.

Click here for the for sale post.

If you can rent one for $20, that sounds like a great
deal. Especially if your semester course only spends
a part of the time at altitude. It would save wear and
tear on your own bag too.

Here is a good price on a -20 synthetic bag at campmore
for just over $200. It weighs under 4 lbs, which isn't
bad for any bag good to -20.

http://www.campmor.com/outdoor/gear/Product___44021.

I do like a synthetic overbag over down myself, but
as long as you don't compress it too much, or wash it
and dry it with heat, the NF synthetic bag should last a
long time and be an option for those future cold or rainy trips.

My friend has a Wiggy's overbag. It is made of heavy fabric
and probably weighs close to 3 lbs. I wasn't impressed.

There is not a synthetic bag out there that weighs under 4 lbs. and will keep you warm at -20*F. In fact, the warmest synthetic bag I ever had/used and of many, was a "Paul Petzoldt Outdoor Products-Expedition Bag" in 1976-78 and HE FOUNDED NOLS. The bag which was warm, VERY hard to stuff on a cold morning and HEAVY, kept me OK to about 0*F and I was young, very fit and USED to sleeping outside in all weathers including B.C. winters.

I replaced that bag with an original Marmot Mtn._Grand Junction Gore-Tex/down bag, custom made for me by Eric Reynolds of MM and THAT bag weighed 4.25 lbs. It DID keep me warm at -20*F and even down to a measured -41*F on Kokanee GLacier outside of my hometown of Nelson, B.C.

-20*F is bloody COLD and a really GOOD down bag, with a bivy sack in eVent and a VBL will keep you warm under such conditions, but, no synthetic bag will..unless it weighs about 10-12 lbs. Go with rental or the Snow Lion and just keep your spare clothes in the foot thereof in a silnylon sack to take up the extra room so your body does not have to heat it.

Alli-

Short version: You're dreaming. Stop. You do need a warmer bag.

You're trying to get a 30*F bag to keep you warm to -15*F. It's not going to happen, no way. Neither a 30* or liner bag are constructed in a way that will conserve your precious heat in those conditions. Now, if you had a 0*F bag and needed another 10*, that might be an option–if you had a bomber hood, a great poofy draft collar, beefy draft tube–double draft tube would be nice.

If anything, your Montbell would be the liner bag for a 0*F bag. But you're definitely not talking about a light or packable/low bulk solution.

You can make do on a lot of the options in your pack. A winter bag really isn't a make-do option. It's your safety insurance. And your comfort. And although it might cost a little more up front, far more economical than the emergency room or funeral bills from trying to take a 30* bag and liner to subzero weather.

Anyone used the Big Agnes Battle Mountain (-15)? It's on the heavy side (5lbs) but it's fairly cheap.

Alli-
One concern with the BA bag is that it's pretty huge inside. Keep in mind that sleeping bags don't produce any heat; they just trap the heat you produce. In other words, you have to heat up the sleeping bag, then keep it warm. Much harder to do in a big bag. You might consider Mountain Hardwear's Lamina series, 0*F if you want a more versatile post-trip option, or -15*F. Priced $185, $225 respectively. Their 600FP down series Clouds Rest 5F @ 325, -15F @ 350. In the spirit of full disclosure, I am a dealer for both these brands and others I might mention, but I'm not trying to or interested in selling you a bag. Just giving you info. There's a couple of North Face synthetics that might be up your alley, too… priced well and decent options. I like that their 0*F Snowshoe, for example, uses Climashield and it comes in womens sizing for under $200. I'd also check the gear swap; there have been a couple of great older down bags on there recently.

What Brad says makes sense. A five pound synthetic also sounds about right. It looks like -10 degree bags made out of the finest down (900 or so) are bit over 3 pounds (if you look at Feathered Friends or Western Mountaineering). So, a single bag with a good synthetic might weigh about five. There is no way you can get two bags which combined weigh 3 pounds and have anywhere near the warmth of the FF or WM bags. It just wouldn't make sense. The FF or WM bags have only one zipper, one inner layer, one outer layer, etc. They are optimized to get you enough room inside to sleep comfortably, and nothing more (wide series versions of the same bag weigh a bunch more). So, the idea that a synthetic weighs about five pounds while a down bag weighs about 3 1/2 makes a lot of sense.

The BA bag comes in a short version. But I'm liking the price of the MH Lamina, it's on sale for $180 at backcountry.com