This winter I have been testing the Arc’teryx IS Jacket and I’ll sum up my experience with two words. Bombproof Furnace! In the category of synthetic belay jackets this one is a beast. Let’s look at the manufacturer description and specs then I’ll jump into some of the finer details and my opinion on the model!
Created for alpine, ice and expedition climbing, the Alpha IS is the single-layer solution for severe alpine environments. The GORE-TEX outer delivers durable waterproof, windproof, breathable protection. Thermatek™, a DWR treated continuous filament synthetic, insulates without absorbing moisture. The combination results in a jacket providing comprehensive weather and thermal protection at a weight 18% lighter than the equivalent midlayer and hardshell system.
Weight 610 g / 1 lb 5.5 oz
Fit Regular Fit, Hip Length
Centre back length: 78 cm / 30.75 in
Activity Ice Climbing / Alpine Climbing / Expedition
How I Tested
I used this jacket for about a dozen day trips this winter including summiting Mount Washington with wind chills around -30f to -40f, alpine ice climbing on Mount Willard with ambient air temps around 10f, top-rope guiding at Cathedral Ledge, and while standing in snow pits teaching avalanche courses in Tuckerman Ravine during mixed precipitation weather.
As I mentioned in the introduction the Arc’teryx IS Jacket is a FURNACE! This is thanks to the exclusive “Thermatek” syntheric insulation which has amazing heat retention properties while being so light and packable. From Acr’teryx:
Exclusive to Arc’teryx, ThermaTek™ is a continuous filament, synthetic insulation that is treated with DWR (Durable Water Repellent) to make it highly hydrophobic, which means that it repels moisture very efficiently. The lofty insulation is then laminated to a backing fabric to ensure an even distribution and insulation.
- Arc’teryx’s most efficient insulation when used in humid and wet conditions
- Very resilient and durable
- The fastest drying fill insulation in our collection
While I am not a fan of this color (it is also available in a much more visible “Magma” color), I found the black color to be even warmer if the belay stance was in the sun.
I also said this jacket is BOMBPROOF, both against all forms of precipitation and winds but also against abrasion. The weather protection comes from the N40p-X 2L GORE-TEX membrane. water-tight zippers, and DWR treatment. The abrasion resistance is thanks rugged shell fabric and fully taped seams.
Manufacturer listed weight is 610 grams, 1 pound and 5.5 ounces. My home scale weighed my size large sample with the storage sack at 680 grams, 1 pound and eight ounces. The jacket easily stuffed into the included stuff sack with measures about 10 x 6 x 6 inches and could be compressed further.
Despite my measurements being a little closer to a medium I went with the large size so it would easily fit over my other layers including a light weight puffy. The sleeve length was perfect and I choose to wear this over my harness at belays. To be honest I don’t know how Will Gadd was leading steep ice while wearing this jacket… it’s too warm! The hood is generously sized enough to easily fit over my helmet.
There are a lot of small design features I liked in this jacket. The elasticized cuffs easily kept snow out and warmth in. The large internal drop pocket kept my water warm and handy while hanging around ice cragging. The stiffened visor kept freezing rain off my face while explaining the Alpha angle to students in an avalanche class in Tuckerman Ravine. The “almost” waterproof chest pocket kept my iPhone protected during moderate rain over the Christmas vacation week. The hood easily fits comfortably over my climbing helmet.
There isn’t much I would change with this piece. A softer piece of material in the “chin” area might be nice but most the time I was wearing this jacket with a buff on anyways. The shell and internal fabric is a bit on the “noisy” side, but that’s such a minor observation I don’t think anyone would notice unless you were trying to stalk a deer or something. And as mentioned, I’d like this more in the Magma color as I prefer high visibility colors for winter mountaineering and ice climbing!
The Arc’teryx IS Jacket is basically the brand’s highest end synthetic belay parka and hard shell jacket in one piece. With a high level of heat retention and protection from wind and rain this really is designed for harsh conditions. I would be hard pressed to find a synthetic puffy and hardshell combo and stay this far under two pounds! Granted the jacket commands I high retail price, but when you consider the price of a separate belay parka and hardshell of this quality I can start to see why it comes in where it does. If you climb in warmer, less harsh, conditions than our local Mount Washington, you might prefer to keep the “puffy” and hard shell as two separate pieces for more versatility, but if you are looking to simplify your clothing system for extreme cold or wet conditions this would be a piece worth looking at!
See you in the mountains,
Northeast Alpine Start
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