Winter Layering System

As Mont-bell uses the terms, a parka has a hood, but a jacket doesn't. For those temperatures, you really want a hood. I had a Mont-bell Alpine Down Jacket and it was fairly warm, but the lack of a hood made it a lot less effective than I thought it should be, especially when there was some wind.

Your winter layers will work well while on the move IMO, (I would likely add a Cap 1 long sleeve to your system). But you will want something with down fill for in camp or long delays/breaks. WM makes nice down jackets and parkas for very cold conditions that I would highly recommend.

Here's what I wear when on the move in temps down to 10 degrees or so

Silk weight polypro long sleeve base layer
Silk weight merino wool long sleeve with collar and chest zipper

If it gets windy I'll add a wind shirt
If it gets below zero I'll add a Montbell synthetic vest

Scott,

You will be working hard on that climb on most routes but you will also be major exposed to extreme winds for most of the trip! Not only think about the thickness of layers but you need to cover every inch of your body and have good seals at your cuffs (legs & arms), waist and head. You will need balaclava and googles along with the best mittens you can find with an additional back-up pair.

My layering system for warmth simply consists of adding merino wool layers until appropriate for hiking on the move. Then I add an appropriate puffy layer for camp.

You will need a serious down parka and insulated pants for stops and carry waterproof raingear. It can be raining at the base that will change to sleet and/or snow as you ascend.

It's a fantastic trip and I hope you have unseasonably nice weather but be prepared for the worst. Check the Mt. Washington Observatory weather forecast and try to be a little flexible on your timing.