You are going on an overnight trip where it could get to zero degrees F. You have a 15 deg down bag, 40 deg down bag, 2 micropuff pullovers and an insulated vest at your disposable. You can also make a VB liner or possibly VB clothes. A snowcave is not gaurenteed to be possible at this point in the season yet. Shelter options are a 3 season 2 man tent, tarp/bivy combo, or bivy only.

What do you bring and why? If you decided you were unprepared and bought an item, what would it be and why?

We do this a couple of times a year from the Phoenix area, where sub freezing weather is unusual, to Flagstaff, where 0 to teens are pretty common. Not many in our troop have bags good to 0,(typically ~ 40F) so we tend to use a double bag approach. Very rough rule of thumb: subtract the temp. rating of the warmer rated bag from 60, then subtract that difference from the lower rated bag. For your bags, that would be (60-40) = 20, subtract the 20 from your 15, and you should be good at 0. If you sleep cold, add 5-10 degrees, and you should be good at that temp. Your pullovers and vest would be insurance / daytime warmth.

Hope that helps,
MikeB

Thanks for the input Mike, I appreciate it. I love ultralight hiking but know my limits too. Winter is a new frontier with much higher consequences, even relatively close to home. Unfortunately I can't test my 0 deg bag setup in the back yard without waiting for a lucky night in a few more months so I'll lean towards over packed for this trip. I'm going to need a -20 minimum bag for a future race so I'd hate to need a single purpose ~0 deg bag.

Have you had any experience with VB liners at 0-15 degs?

Chris, my experience with VB liners indicates that for temperatures above zero, their benefit is marginal and their comfort is poor.

Below zero, their primary benefit is preventing condensation from entering your bag and collapsing loft on a long trip.

I prefer the comfort of a synthetic bag and clothing without a VB liner for most of my winter trips. I'll still take a down bag on overnighters, and I will use VB for extremely cold conditions.

Ryan, maybe you have been exposed to bothy bags, I'm not sure where the weight hits or if there are any ultra light ones out there, I have an older one that must be around a pound, but they come in 1,2, or more person sizes, pretty popular with UK climbers and Scottish highlands wanderers for getting out of weather and stretching temp ratings.

> Shelter options are a 3 season 2 man tent, tarp/bivy combo, or bivy only
No hesitation about taking the tent. At least you have some chance of getting out of the weather. OK, my 3-season tent is a 3-pole tunnel and fairly storm-resistant, but my point stands.

Down to 0 F? 15 F bag and a micropuff - and some thermals, and a partner you can snuggle up to! (I take my wife.)

VB? I would not bother for one night.

Buy an item? Maybe a good winter canister stove and some cocoa.

Thanks Roger. I will bring the tent for this first go. I really like bivy sacks but I need to learn my limits in winter a bit cautiously so I'm allowed longer solo trips. In the worst case I will find a sheltered place to pitch it. If I'm lucky I will practice making a snow cave as well but I'm unsure of the snow level at this point.

I'll be taking some combo of bag and clothing. Such a pity my 15deg bag was purchased pre BPL. My purchase of a -20 bag will probably yield a lighter and warmer product, albeit considerably more expensive.

I've got a Coleman Extreme on the way for a stove with a 1L pot for snow melting. Does that seem appropriate? Cocoa and cookies are on the menu along with the usual cold weather edible fare, aka not PowerBricks.