Although the Alpha FL is one of our favorite hardshell jackets, it lacks a few features that some users will miss, such as underarm vents and hand pockets.
The Alpha FL is our favorite lightweight hardshell for mixed climbing on ice and rock because it's Gore-Tex Pro fabric can handle considerable abrasion without getting damaged.
This jacket comes close to perfection in terms of weather protection. Although we like the comfort offered by the neck cuff on the Arc'teryx Beta AR a bit better, we think the standard collar of the Alpha FL still did a great job of keeping water out in our shower test.
The storm hood was the best one that we tried, with three pull-cord adjustment points, one in the back and two in the front. It also fits great with a helmet on. Additionally, the zippers are watertight and incredibly easy to operate.
The hood adjusts with a pair of drawcords on the front and a single cord in the back. In our shower test the reinforced brim was effective at directing water away from our tester's face.
The jacket is made entirely of 40-denier face fabric and Gore-Tex Pro, which offers fantastic protection against rain, wind, and cold. This fabric, however, isn't quite as burly as the 100-denier fabric on the Alpha SV. The wrist cuffs are also a little slimmer, which means they are slightly more prone to accidental opening. These small critiques aside, the Alpha FL still offers exceptional weather protection overall.
Three months into testing, the 40-denier Gore-Tex Pro fabric was still beading water like a champ.
A size large tipped our scale at 11.8 ounces, making it one of the lightest models in our review.
There are a couple of jackets that weigh fractions of an ounce less, but none of these lightweight rivals can boast close to the same level of durability.
The Alpha FL's stuff sack has a sewn loop that you can back up with the cinched drawstring for redundancy when clipping it to your harness.
This jacket also comes with a nylon stuff sack. Although this sack adds a little weight (0.3 ounces) and it's one more thing to keep track of, we prefer it over stuffing a jacket into its own pocket because a separate stuff sack offers an extra barrier to protect your expensive shell. It's also particularly useful with a minimalist jacket like the Alpha FL because the jacket's limited venting options guarantee that you will be taking it on and off regularly to avoid sweating.
Mobility and Fit
Our head tester for this review is 6'2" tall and weighs 175 pounds. He has fairly broad shoulders, but an otherwise skinny frame, and we ordered him a size large jacket for this review.
The athletic fit of the Alpha FL was excellent in the arms, shoulders, and chest, but it has a confusingly short hem in the front. Despite his best efforts, it was routinely coming untucked from his climbing harness.
Although shorter folks didn't seem to notice, a short front hem is the chief complaint from this 6'2" tester, seen here in a size large with base layers exposed after raising his arms overhead.
This jacket is shaped according to Arc'teryx's Trim Fit, ensuring that it is low volume. In fact, it has one of the best and most practical fits for climbing or backcountry skiing when you won't be wearing a ton of insulating layers underneath. However, there are much better options for lift-access skiing or low-intensity cold weather activities when you would want to bundle up. As is typical with jackets that use a Gore-Tex Pro membrane, the jacket is mildly stiff and noisy when moving about.
Venting and Breathability
Like a lot of jackets in this review, the Alpha FL uses a dependable Gore-Tex Pro waterproof-breathable membrane. To "breathe", the Pro membrane uses solid-state diffusion, which moves water trapped within the coat to the outside world.
For this to happen, the relative humidity within the jacket must be higher than the corresponding humidity outside of it. In practical terms, this means that inside the jacket, you may feel hot and moist for the gas exchange to occur. That is why many Gore-Tex jackets also incorporate pit zips for direct airflow ventilation.
If sun peeks out you the Alpha FL lacks pit zips for venting excess heat. The Gore-Tex Pro fabric is also not particularly breathable.
Without pit zips or other methods of ventilation, we scored this jacket relatively low for venting and breathability. We found it to be hotter and sweatier during our stationary bike test than some of the jackets that incorporate air-permeable membranes, like Outdoor Research AscentShell or The North Face Futurelight fabrics. Honestly, this is one drawback of this jacket, but it made little difference on cold days when we only worked hard intermittently. On warm days in the sun, this presents a much more significant problem, but it's easily solvable by taking the jacket off.
Features & Design
Designed with efficiency and weight savings in mind, the Alpha FL is a bit lacking in features, notably pit zips and handwarmer pockets. The features it has, however, are thoughtful and well-performing. It has only one napoleon-style chest pocket.
While some may consider this a drawback, we have found that for alpine climbing, handwarmer pockets can be challenging to use and uncomfortable under a climbing harness. The storm hood is enormous and works pretty much perfectly with or without a helmet. The zippers are durable and super easy to pull with gloves on, which is a huge plus.
The wrist cuffs on the narrow Alpha FL sleeves use a pretty basic hook and loop closure system. In our tests, we found they stayed in place better when tucked inside our gloves rather than over the top.
The two cord lock buckles on the side of the hood, as well as the dual buckles on the hem, are Cohaesive cord locks; this is a huge positive because they are sewn inside the layers of the jacket, low profile, and very easy to release with gloves on. While we found the feature set nearly perfect for alpine climbing, it still works pretty well for skiing. The most prominent caveat is that it doesn't include the vents common in most ski-specific jackets, but in Colorado and California, we just took it off if the going got too hot, and when we needed it for storm protection, this was never a factor.
An Alpha FL might be overkill for rainy hiking, but if you already have one it also excels at the activity.
Hardshells aren't cheap, and the Alpha FL certainly isn't. However, if you need a real a hardshell, you're going to have to shell out some serious cash. When you do, you can rest assured that you're getting a great value with this jacket. It's possible to spend double the money on one of its competitors, but it's impossible to find better all-around upper body protection.
The Gore-Tex Pro fabric on the Alpha FL feels substantially more durable than the fabrics used on other ultralight hardshells. Even pointy ice screws have a hard time putting a hole through it.
The Arc'teryx Alpha FL is a top-quality, high-performing hardshell with exceptional engineering and design. It is the quintessential hardshell: it's lightweight and durable and offers incredible weather protection. It also fits pretty much perfectly. For eight years running it has been our Editors' Choice Award winner, and for good reason. It's a solid choice for anyone aspiring to go fast and light in the mountains.