Arc’teryx Alpha Shell Jacket Comparison

So you’ve decided you need a new Gore-Tex shell for all your climbing endeavours. Maybe need isn’t the right word — want? Desire? Covet? Regardless of motivation, let’s say that Arc’teryx is your chosen brand, but which alphabet soup shell do you choose? Alpha? Beta? Zeta? Cassiar — this one isn’t even part of the Greek alphabet, it was all making sense, but now I’m so confused!?

Overhanging mixed is a great test of breathability. Photo by Jana Mikova.

Given that you’re reading this website, I will assume you want a climbing shell. In Arc’teryx-speak that means an Alpha, but which one to choose? There are three, possibly four, models to choose from, depending on your aversion to past-season models. They are, from heaviest duty to lightest:

Alpha SV — “SeVere” use, this is the jacket that started it all for Arc’teryx as a garment company when it was introduced in 1998. It has undergone continued refinements and updates and this latest FW20 version uses the new Most Rugged version of Gore-Tex Pro. The SV uses a heavyweight 100-denier face fabric to create what Arc’teryx says is “the most durable product we know of.” 

Alpha AR — “All aRound” use makes this probably the most versatile of the climbing hardshells. It also uses the new Gore-Tex Most Rugged fabric but at a significantly lower weight: 40-denier through the body, with more durable 80-denier reinforcements on the hood, shoulders, and the outer side of the sleeves.

Alpha FL — “Fast & Light” use designed with light weight and minimalism in mind. The FL uses Gore-Tex Most Breathable for higher breathability through the body and Gore-Tex Most Rugged over the hood, upper back and shoulders for extra durability. Both fabrics are a lightweight 40-denier. (This jacket has been replaced by the Alpha AL Anorak as of Spring/Summer 2021.)

Alpha SL Anorak — “Super Light” use emphasizes light weight and packability over long-term durability. This is new for Spring/Summer 2021 and uses an Arc’teryx-exclusive version of Gore Tex that is paired with a proprietary 20-denier face fabric, which in turn is reinforced with a 25-denier Liquid Crystal Polymer ripstop grid. All of this combines to be called Hadron 3L Gore Tex. (This piece has replaced the Alpha FL as of Spring/Summer 2021.)


As one would expect, the jackets range in features from most to least, following their respective design philosophies. They all have an embedded Recco reflector, which is located at the back of the hood in all except the SV, which locates it in the left bicep pocket. All of them also have Arc’teryx’s superb StormHood which, as I’ve written before, is one of the best helmet-compatible hood designs on the market, allowing complete protection with unrestricted movement.

All the Alphas also share one of my continued frustrations with jacket design: overlapping pockets. I get it, most people are right-handed but these are supposed to be alpine climbing shells and every alpine climber I’ve ever met is admirably ambidextrous — we all swing tools, place gear, clip ropes, and perform any of the myriad other climbing tasks with either hand. I think it’s fairly safe to assume we could access a pocket with our non-dominant hand. I find this especially frustrating on the more minimalist shells on which both the inside and outside pocket are on the left side. And don’t even get me started on left-side pockets on every piece, from base-layer through mid-layers all the way to belay jackets!

The SV has two large outside chest pockets which are gusseted towards the outside for extra capacity, and a small pocket on the left bicep. This bicep pocket is tiny, and just barely fits my (ancient) iPhone 8. It’s big enough for a couple of bars but that’s about it — I’m honestly not sure what the purpose of such a small pocket is, other than a place to put the Recco reflector. Inside the jacket, there’s that zippered pocket on the left side and a fairly sizeable mesh drop pocket on the right. The inside pocket is good for keeping some small snacks from freezing or a place to put your phone so it can get soaked in sweat (aka mostly useless) but I absolutely love the drop pocket for keeping gloves warm and dry: why don’t all hardshell jackets have a drop pocket like this?! The SV also has pit zips for extra venting.

The left bicep pocket is big enough for some energy bars, but not much else.

The AR also has two large outside chest pockets, though these are less capacious than those on the SV. There’s that typical too-small inside chest pocket (on the left, where else?) and pit zippers for dumping extra heat.

The FL has just one outside chest pocket, smaller still than the AR’s, and of course that nearly-useless inside chest pocket, on the left side.

The SL has just the outside chest pocket, which feels even smaller than the FL’s though my measurements show it to be slightly wider but with a smaller zipper opening. (But, rejoice! No inside pocket — finally!)

Outer Chest Pocket Size

The measurements are the length of the zipper, and the width of the pocket. I couldn’t figure out a reasonably accurate way to measure the effective depth of each pocket. See images below for how I measured.

SV – 19cm zipper x 16cm wide
AR – 17cm zipper x 15cm wide
FL – 17.5cm zipper x 14.5cm wide
SL – 14.5cm zipper x 16cm wide

In use, the outside pockets on the FL and SL feel to be about the same size, and are big enough to stash a mid-weight pair of gloves. The AR’s pockets feel a bit bigger, and the SV’s are bigger still, and are spacious enough for a fairly heavy-duty pair of belay gloves.

I wish all the jackets had the mesh drop pocket of the SV: it is by far the most useful feature on a hardshell that I can think of. Actually, thinking about it, I’d prefer if the inside zippered pocket was dropped in favour of two, somewhat smaller, drop pockets on either side — this would be ideal for long routes where I want to keep multiple pairs of gloves warm and dry. And, let’s face it, I most likely already have another small, zippered, chest pocket on either my base-layer or mid-layer (or, even more likely, both) so don’t really need another one in my outer shell.

The Alpha SV’s superb right-side drop drop pocket.

All the jackets have hem drawcords, though the SL makes do with just one adjuster instead of the two found on the heavier shells. Interestingly, as the jackets get lighter so do some of the other features: the Velcro pull-tabs on the FL are almost half the size of those on the SV, and the zippers are more minimalist as well.

Fit & Cut

The differences in fit is what surprised me most about these jackets. The SV and AR are both Regular Fit, while the FL and SL are Trim Fit. Arc’teryx defines Regular Fit as “cut comfortably…for a classic fit” while Trim Fit is “cut slim…for a low profile fit.” The FL and SL are definitely quite trim and tapered, and the AR is about what I would expect from a hardshell jacket, but the SV feels like it’s a size too large for me — despite all the jackets being Men’s Medium.

L to R: Alpha SV, Alpha AR, Alpha FL, Alpha SL.

Other than the different “fits,” the jackets also have slightly different hem cuts. The SV and FL have what Arc’teryx calls a “Drop Hem,” which means the hem drops at the rear by more than 5cm. The AR has a “Slight Drop Hem” which also drops at the rear but by less than 5cm. I haven’t found any information about the hem on the new SL, but it appears to be a “Slight Drop Hem.”

L to R: Alpha SV, Alpha AR, Alpha FL, Alpha SL.

The SV’s fit is generous to say the least, and one of my longtime climbing partners even thought that I was wearing a jacket one size too large (and he’s very used to me showing up with random new clothing and gear). The high-denier fabric makes this feel like a suit of armour, but it also contributes to the SV’s slightly inflexible feel, which isn’t as soft and pliable as the other jackets. It also crinkles slightly when moving, akin to hardshells from a decade ago. The hem is long and the sleeves loose, and fit through the body is overly generous. The SV feels like it was designed to be worn over two or three insulating layers, not the single mid-weight mid-layer that I usually wear when winter and alpine climbing. This is a big, burly, jacket which honestly feels like overkill for everything but the harshest conditions.

The AR feels like a much trimmer jacket, and fits like I would expect a hardshell to fit. The sleeves and hem are long, and fit through the body is roomy but not loose. The lower-weight fabric feels softer and less crinkly than that of the SV, even in the 80-denier reinforcement areas. This jacket feels like it was sized for how I’d typically use it, with one mid-layer underneath, but also has enough space left that if I had to add another layer on really cold days there’s enough room to accommodate it. It’s roomy but not loose, if that makes sense.

The FL is cut in what North Americans often refer to as Euro-fit, which is to say it’s trim and form-fitting. It feels like a different sized jacket, especially compared to the SV, yet he sleeves are still long enough to keep my wrists covered when reaching up (and looking at the side-comparison photos, even longer than the SV or AR), and the hem has never pulled out from under a harness. It has room for one mid-weight mid-layer but that’s about it, though I feel I could stuff a second one underneath but it’d be a bit tight. This is very much a trim jacket, designed for active use in the mountains, without any extraneous features or much extra room for layering.

The SL feels very similar in fit to the FL, though it feels a touch roomier, especially through the chest. The sleeves feel even longer than the FL as well. It easily fits over my standard mid-layers, and like the FL I think I could stuff a second mid-layer underneath but it would start feeling a bit tight. Because it is a pullover it is more awkward to put on than a full-zip jacket, but I think it’s this slight bit of extra room that gives it that marginally roomier feeling when compared to the FL.


The SV and the AR are both Gore-Tex Most Rugged, which is rated at RET 9: not the most breathable out there but it works well enough. The FL’s Most Breathable membrane comes in at RET 6, while the SL’s Arc’teryx-exclusive Hadron 3L Gore-Tex is apparently similar in performance to Most Breathable. However, due to the lightweight fabrics of the SL, it feels even more breathable and supposedly rivals Gore Shakedry, which comes in at RET 3. But what I find even more significant  in terms of breathability than these ratings is fit and cut.

The trim-fitting Alpha FL feels quite at home on steep terrain — I was surprised I didn’t have to ditch layers! Photo by Tim Banfield.

First, let’s backtrack a bit and discuss insulation. To put it simply, captive air is the best insulator out there. All insulated jackets work on the same principle: various designs of fibres provide loft which creates captive air pockets which in turn keep air trapped between them. Your body heat warms up this air, which is kept captive thanks to the inner and outer fabrics and various baffling sewn into the garment. More warm air means a warmer jacket. This is why down is such an effective insulator: it has incredibly high loft for its weight and creates an incredible array of air pockets.

Breathability is a bit more complicated, even in simple terms. What we’re looking at it is differential pressure, which is the relationship between the inside (underneath the jacket) and outside (as in, the outside outside) environments. The inside of a jacket is often warmer and more humid than the outside, and because the natural state of the world is for things to equalize, the vapour inside tries to escape to the outside to even things out. This is where the vapour permeability of a jacket comes into play — commonly called breathability — and influences how well and how quickly a given garment dumps excess heat, aka water vapour. This is most often accomplished via synthetic membranes, which ‘breathe’ thanks to the larger size of the pores as compared to the size of the water vapour droplets trapped inside.

Another factor to consider is the face fabric used: lower-denier fabrics are, essentially, thinner, which creates less of a barrier for water vapour to escape. A 100-denier fabric will be less breathable than a 20-denier fabric even if the membrane is the same, simply due to the different thicknesses of the threads and fabrics.

Finally, let’s add in another aspect: fit. The looser a jacket is the more air it traps, which makes it feel warmer. This extra space also makes it harder to build up sufficient differential pressure for the membrane to work at its best. Therefore, a trimmer-fitting and more body-hugging jacket will feel like it’s more breathable than a jacket using the exact same fabrics simply due to the fit and the amount of air trapped between your body and the garment.

Now apply this same concept — trapped air — to our hardshell jackets. The SV fits quite loose, which means it traps a lot of air, and therefore feels warmer and less breathable than its trimmer-fitting siblings. It also uses a much heaver 100-denier face fabric throughout. The trim FL and SL feel the most breathable by far which makes sense given that they trap the least amount of air, use the most breathable membranes, and also use lighter 40- and 20-denier fabrics, respectively. As expected, the 40- and 80-denier AR falls somewhere in between: it doesn’t get too hot, but neither is it as effective at dumping heat as the FL and SL.

The Alpha SL feels more like a windbreaker than a fully-waterproof Gore-Tex shell.

So if you’re looking for the best performance, don’t just look at the fabrics and membranes but pay a lot of attention to the cut and fit of the jacket, and take into account your base- and mid-layers. Fit is by far the most important factor in the breathability of a hardshell that I’ve experienced.

Weight, Price & Value

SV – $950 CAD – $799 USD – 510g quoted – 504g actual (Men’s Medium)
AR – $750 CAD – $599 USD – 430g quoted – 426g actual (Men’s Medium)
FL – $550 CAD – $475 USD – 340g quoted – 326g actual (Men’s Medium)
SL – $500 CAD – $375 USD – 210g quoted – 208g actual (Men’s Medium)

It’s hard to believe we live in an age when a hardshell jacket costs almost $1000 (Canadian, anyway). Of course, Arc’teryx isn’t the only brand with jackets this expensive (Mammut and Norrona are two prominent others that immediately come to mind), so let’s not dwell on just how incredibly expensive some of this gear has become. (But yes, it is a bit crazy.)

You can — almost — buy both the SL and the FL for the price of one SV, and the AR is a tempting middle-ground proposition. The SV, for me, is too burly and too bulky and just too overkill for regular use. If you’re planning an expedition into remote mountain ranges (not to say that some areas of the Canadian Rockies aren’t remote) where you might spend weeks living out of your clothing and need the absolute highest waterproofness and durability or are planning to spend a lot of time in extremely wet conditions, or just run cold and want to wear a couple layers underneath, then the SV makes sense. But I couldn’t justify $950 for this jacket otherwise — no matter how much I like the inside drop pocket, it just isn’t worth $200 over the AR.

The decision between the AR, the FL and the SL is more nuanced. I prefer the trim fit of the FL and SL but really like the dual pockets of the AR, and the option to possibly add more layers underneath. But is that worth the additional $200? I really don’t know. And are the arguably more durable fabrics of the AR worth it over the FL/SL? I honestly can’t say one way or the other, either. I have yet to damage a Gore-Tex jacket, though I’ve torn many pairs of Gore-Tex pants with either crampons or ice screws. I’ve scraped my helmeted, hooded, head on numerous rock outcrops and snagged my jackets on so many rock bits that I’ve lost count but I’ve yet to actually put a proper hole into a hardshell jacket. Maybe I’m just not trying hard enough. I’d say this is a tie between the AR and the FL/SL duo, though the dual chest pockets and slightly roomier fit make me think the AR is the better overall value.

The light and versatile Alpha FL is my favourite late-season wet-ice warm-weather shell.

However, the FL and the SL present very tempting propositions. The FL is a great lightweight shell, assuming you don’t need to add multiple layers in cold conditions. The SL is so incredibly light that you’d probably bring it on every outing, and it is also the most breathable of the four jackets so you’d be more likely to wear it regularly. I wish the SL had a full-length zipper — as is, the zipper is about 2/3 of the jacket in length, and adding another 1/3 of a zipper length can’t possibly add that much weight, but it would make this a much more versatile shell.


In my opinion, the AR and the FL are almost equal other than pockets and price. Either is a great choice, and I would try to base my decision on fit and expected use: FL if you have more than one hardshell, or always climb in similar conditions, the AR otherwise as it’s more versatile with accommodating extra layers, and I do really like the dual outside pockets.. The SL is almost in a league of it’s own: much lighter than the others, more breathable, and even more stripped down. I’m not a fan of the pullover construction, but in terms of functionality I simply can’t fault it. This is definitely not a one-jacket but if you want to add an ultralight hardshell to your closet I can’t think of a better choice. Unless you really (really, really) need the extreme durability, or the oversized fit, I’d stay away from the SV as it just doesn’t seem worth the extra cost.

The Alpha SL is breathable enough for warm spring days, though it is so thin and light I am afraid to shred it on every outing!

Alpha SV — only recommended if you require the extreme durability or roomier fit to accommodate extra layers.

Alpha AR — this is my overall recommendation from the Arc’teryx Alpha lineup: great fit, excellent breathability, dual outside pockets, plus it’s the more versatile choice if you ever need to add an extra layer.

Alpha FL — great choice if you don’t require a lot of layering versatility, or if this is going to be your lightweight  hardshell. Or if you have a slimmer build and the trim cut just fits you better.

Alpha SL — the most minimalist shell here and I’d pick this only if this was going to be a second (or third) hardshell in the arsenal. If that’s the case, it’s a superb choice.

The Alpha AR is my overall choice for climbing hardshells from Arc’teryx.

A very sincere thank you to Arc’teryx for sending all these jackets for a comparison: articles like this wouldn’t exist without the support of the brands that make this gear. As always, the opinions expressed here are my own and I don’t get paid to do any of this, nor is there any expectation from the brands for me to write positive reviews.

Arc’teryx Alpha Shell Jacket Comparison