Parka and hardshell - sizing dilemma

11:59 a.m. on December 15, 2013 (EST)
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Hello, I need a bit of advice regarding sizng and layering.

I am preparing for Aconcagua expedition. I have decided (after waaaaay too much research and hair splitting) that my top layering system will include: (1) arcteryx thick base layer sv (thinner for lower altitudes) (2) pata r1 fleece (3) arcteryx atom lt - insulation mid layer / main jacket for lower altitudes (4) arcteryx beta lt - hardshell (5) rab neutrino endurance - down parka

I have doubts, however, as to sizing.

I have chosen beta lt as the nicest fitting hardshell - it works great on top of my atom lt and without it. I have it in small size, same as the atom.

As regards the parka - size small fits generally ok/trim-fitted, it is my true size. It works great without the atom, and is alright with atom. However, it seems quite a bit stretched when fit over the hardshell - especially in the neck area, when I try to zip everything up.

Hence the query - should I go for Small size or get a medium?

My thinking has been that a parka is mostly used in a camp without much other gear. However, I will definitely also use it on the summitting day. I might also use it in the future when belaying on other trips, which means putting it on top of the hardshell...

How do you usually size your parkas? Do you go for a size bigger?

Thank you for your help!

1:17 p.m. on December 15, 2013 (EST)
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I think going big enough to comfortably fit over everything else is the way to go. In belay or rest situations being able to just put it on over everything and then take it off and still have everything on is convenient.  It helps if the parka has a long tail and good gathering system so even if you don't fill it up you can at least seal it off.

7:37 p.m. on December 15, 2013 (EST)
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Definitely size up, always size up those outer shells for winter use.

1:19 a.m. on December 16, 2013 (EST)
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Aconcagua can get mighty cold (and windy, which adds wind chill factor). But while you are on the move, you will generate a lot of body heat. I find that I rarely would want a full parka except in camp.

On the move, the Atom LT under the Beta LT will probably be fine for summit day (assuming expedition weight base layer and midlayer top and pants). But the Atom uses Coreloft, which is similar to Primaloft, hence you will want to have room to expand the Coreloft without compression. Definitely, the shell should be a full size larger than the comfortably fitting Coreloft (the Coreloft, remember, also has to fit over your expedition weight base layer and midlayer). If possible, try the whole set on to see that you allow the inner layers to get full loft.

As for the Endurance jacket, you will most likely find that you will only wear it in camp (the camps above the base camp, which will be moderately warm) and when stopped for rest breaks, and during the 15-20 min you spend on top getting your picture taken.

The photo below was taken on Kilimanjaro, a slightly warmer peak than Aconcagua.

I had an expedition set of long johns, a flannel shirt, a R3 fleece jacket and a Wild Things eVent hard shell, and was plenty warm. 

The photo below was taken on the summit of Denali, wearing a similar set of clothing (shell was a Marmot Alpinist 3 Goretex jacket. Temperature was a balmy -10F and virtually no breeze.

The photo below was taken on Mt Vinson (Antarctica, temperature was -35F at the time).


The major difference among the 3 photos was the boots. In the Kili photo, I was wearing my Lowa full leather boots. On Denali, I was wearing Scarpa Invernos with Intuition liners. On Vinson, I was wearing La Sportiva Olympus Mons.

The important point here is that in all 3 cases, the outer shell was sized one size larger than usual to allow the layers underneath to be relatively fully uncompressed.

10:02 a.m. on December 16, 2013 (EST)
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Thank you very much for the quick responses - I truly wish I could reciprocate somehow your kindness!Let me know if you ever happen to be in London - all beer is on me!

As suggested, I have gone with a parka one size up (medium), just for the sake of 100% comfort, and to make sure that the down is not compressed too much. It might be a bit loose without all the other layers but hey - I am not going on a fashion parade, but on an expedition.

On a separate point, I have been constantly thinking (and overthinking): I bought Arcteryx Beta LT which fits nicely. But... should I maybe trade up to Alpha LT? Alpha has much more relaxed fit (seems too big, even with my Atom underneath), but maybe that's how it is supposed to be? Alpha SV seems like an overkill, even for Aconcagua/Denali/anything else I might do in the future. But Alpha LT might not be as bad.

The main difference between Alpha LT and Beta LT is: much more relaxed fit (seems way oversized) and pit-zips.

What do you think?

3:50 p.m. on December 16, 2013 (EST)
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i assume you have tried on the RAB.  most of their jackets run small; the Neutrino actually runs true to size because it's designed as a belay jacket. 

i would think it's warm enough for Aconcagua, when you aren't moving. 

the rest of your plan sounds very solid.  have a great trip - be careful!

July 21, 2018
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