This four-season three-layer alpine shell is light. At less than twelve ounces for a large the Alpha FL is actually lighter than most three-season two-layer rain jackets on the market, including Patagonia’s TorrentShell, OR’s Forray, or Marmot’s PreCip. At least a few oblivious online user reviews of the Alpha FL say things like “this is the best rain coat I’ve ever owned!”
But don’t underestimate this shell: it belongs in the wind, ice and snow. The 40-denier facing fabric is the second-toughest that Arc’teryx uses in mountaineering jackets (after only the 80-d), and the GoreTex Pro membrane is the burliest waterproof/breathable membrane produced by W. L. Gore. Marketing lingo aside, the design philosophy of this jacket couldn’t be simpler: take a full-on mountaineering shell and reduce its weight to a minimum by stripping out all of the dongles, but without compromising on materials or construction. The end result, at least in theory, is a shell well-qualified to handle the worst winter weather, yet small and light enough to toss in a summer pack. It’s a concept so sensible yet unexpected that it’s no wonder online reviewers are confused.
Arc’teryx’s huge catalogue can be daunting. Each product line (Alpha, Beta, etc.) has a different cut based on the intended activity, and each product designation within a product line (severe weather (SV), fast-and-light (FL) etc.) is cut differently to accommodate different conditions. The Alpha is Arc’teryx’ alpine climbing line, which feature short cuts intended to stay out of the way of a climbing harness, and sleeve designs that prioritize range of motion. The fast-and-light (FL) designation means that the jacket is designed for high-output aerobic activity where light weight is paramount.
What does this mean in practice? Overall, the Alpha FL is a carefully fitted yet moderately roomy cut. Arc’teryx specs it for “light layering,” and though the jacket can accommodate a base, fleece mid, and light down insulating layer without feeling claustrophobic, it’s happiest with one midweight mid layer. The armpits are cut somewhat high and upper-body range-of-motion is excellent.
When Arc’teryx says the jacket is cut short in front, they mean it. The hem of the jacket is fairly normal in the back, but sweeps up toward the front, and the bottom of the front zipper sits near the middle or top of my belt. While I enjoy the freedom of movement at my waist compared with long ski jackets, the cut is so short that mid layers (including the shortest-cut mid layers from Arc’teryx itself) peek out from below the shell and are exposed to the elements. I don’t think that this makes a significant functional difference, but it can make you feel a little exposed up front.
The hood is just big enough to accommodate a ski helmet, and cinches down snugly over a hat.
The Alpha FL is built entirely out of a DWR-coated 40-denier facing fabric over a GoreTex Pro membrane. While several other Arc’teryx shells feature a heavier-duty 80-denier fabric, I can’t imagine needing it. I’ve spent over a year bashing the Alpha FL against rocks, scraping it on branches, and even using it as a sled. Though the DWR wears off (as always), the shell material itself has held up through everything.
Some online reviews complain about the “crinkly and loud” GoreTex Pro membrane. In my experience, this is the kind of complaint that really only holds water if you’re doing your mountaineering in a quiet showroom. Yes, the shell material makes a slight rustle but when the weather is harsh enough that you need a shell, you either won’t notice how it sounds or won’t care.
As expected, Arc’teryx nails the details. The stitching is immaculate and the seams are all carefully taped. Drawcords, cinches, and even zipper pulls are all built right. The velcro on the Alpha’s cuffs is the best I’ve ever seen.
I’ve used the Alpha FL as a hiking shell in the spring, rain coat in the summer, alpine ski shell in the winter, and as a paddle jacket on packrafting trips. There’s an old truism about gear that you can buy specialized items that perform brilliantly in their niche, or buy generalist items that are mediocre at everything. And to be sure, the Alpha FL isn’t perfect for all conditions or activities. Alpine skiers might miss a powder skirt. Pit zips would be nice for warm weather. The Storm Hood on the Beta, Theta, and some other Arc’teryx jackets arguably adds more protection. But the simple truth about the Alpha FL is that it delivers on its most important promise–keeping you protected from snow, wind, and rain in cool/cold conditions–without any apparent compromise. In short, this thing is bombproof.
So where is the Alpha FL simply the wrong choice? This is really a function of the heavy-duty shell material and membrane, which will be challenged by a combination of high aerobic output and high temperatures. The shell’s ability to breathe will be overpowered if you seriously start to sweat, so it’s a poor choice for, say, an after-work run. As a general rule of thumb, the Alpha FL is appropriate for environments where you could conceivably be in sight of snow. If it’s consistently warm or hot, there are lighter, looser shells that will retain less heat and vent better. At heart the Alpha FL is an alpine climbing shell with enormous range, but it is still an alpine climbing shell.
If I could only own one shell, this would be it. It’s lighter than most three-season rain coats, yet provides enough protection to shut out a subarctic winter storm. Downhill skiing at -10? Check. Summer backpacking trip in Alaska? No problem. Yes, the Alpha FL strips out features found on other shells. But by paring things down to basics and then executing the basics almost perfectly, I trust the Alpha FL to keep me safe in just about any cool or cold-weather conditions.