Arcteryx LEAF Atom SV

Background

First released in 2009, the Atom SV is described as a cold weather jacket designed to provide significant warmth, wind resistance with a roomy fit to be worn over other layers or gear. The Atom SV Hoody is a deceptively lightweight and low profile jacket for the warmth it brings to core body areas. The exclusive Coreloft™ synthetic fill used in the Atom is a highly efficient insulation that effectively traps and holds warm air next to the body even when wet.

The SV uses a DWR treated, 30 denier nylon face fabric called Gossomera instead of the 20 denier Luminara  fabric used in the LT and has 100g Coreloft fill instead of the 60g found in the LT. While the Atom LT (LT = light) is more suited for use as light mid layer for high aerobic activity, the Atom SV (SV = Severe) is designed to provide a step up in warmth and durability and is capable of being worn as a light standalone jacket in cold/dry weather condtions.

Feature Highlights

Gusseted Underarms and Articulated Shoulders and Elbows – This design allows for an unrestricted range of motion making it suitable as an active jacket. The articulation in the elbows helps to minimize sleeve lift when extending your arms such as while shooting in prone or during ladder ascents.
Insulated Hood – The Atom’s hood is designed to be adjustable, allowing it to fit securely around the head and face so you can turn your head naturally without it obscuring your peripheral vision. There are two shock chord pull-tabs located at each side of at the base of the collar at the front, which adjusts the opening of the hood. Another shock chord pull tab is located at the back of the hood that adjusts the circumference of the top. The Hood on the Atom SV also features a semi-stiff brim to help keep snow off your face.  The hood is designed to accommodate most helmets, though I found that it just barely fit over my FAST helmet when equipped with the ANVIS LPBP and Peltor ARC rail adapters. When not in use, the hood also serves as a high back collar which helps keep wind off the back of your neck and can also be ‘stowed’ using the built-in hanger loop.
2 x  7″ x 9″ Low Profile Hand Warmer Pockets – These pockets are lined with a soft micro fleece-like material and are equipped with media ports to allow for internal routing of communications cables. The zips to the side hand warmer pockets are hidden, with the zipper opening tucked neatly into the seam under a half inch flap which also provides added protection from the elements. It would have been nice if they had moved the pockets high enough up the chest to allow access to these pockets while wearing a plate carrier though.
7″ x 6.5″Internal Chest Pocket – This inner chest pocket on the left side has a zipper closure and is great for keeping your credentials or smart phone.
Vertically Routed Hem Drawcord – Unique to the LEAF version, this design is intended to minimize interference with belt worn kit.
YKK Vislon Zipper

Stretch Wrist Gaskets – The cuffs are made out of  a lycra stretch fabric giving them an extremely low profile and are compatible with most gloves. The cuff is one of the most comfortable designs I have seen and are made to hug the wrist to help retain heat.
4″ x 4″ Velcro Loop Panels –Located on each shoulder, these Velcro loop panels are designed to allow you to affix IFF tags and other similarly sized Velcro backed items.

Materials and Construction:

Gossomera Face Fabric –This 30 denier Nylon Ripstop Fabric is DWR coated, breathable and serves an effective wind barrier. While not ‘waterproof’ by any means, the DWR treated face fabric effectively sheds light rain and moisture.

Coreloft™ Insulation – This 100% polyester insulation is extremely thermal efficient, and has a very high warmth-to-weight ratio and is designed to resist compacting.  Coreloft is constructed using a two types of polyester fibers; the finer strands increase thermal efficiency and the thicker strands  are siliconized to provide loft, resistance to moisture, decrease drying time and help Coreloft fill to bounce-back when compressed.

Size and Fit (I am 5.7 about 172lbs)

Photos above: I have included 2 photos of the non-LEAF version of the Atom LT to illustrate the differences in fit.

While the Atom generally tends to be more fitted compared to other Arcteryx insulated layers, as with all of the LEAF garments, the LEAF version of Atom is intentionally built roomier than its civilian counterparts to allow more layering and when worn over body armour, chest rigs etc. The Atom is a waist length jacket with a drop back hem which lines up almost perfectly with the hem line of the Alpha LT.

That said, the Atom SV’s overall outline is not as puffy as the Cold WX and at least for a guy like myself, who is about average height with relatively shorter legs, it doesn’t make me look as top heavy.

Conclusion and Insights

There are 3 main components to an effective layering system; a base layer, a mid layer and an outter layer.  As a general rule, an ideal base layer should be fitted, moisture wicking and maintain its insulating properties, while the mid layer should capture the warm air, but should also breathable. The terminal layer should be both breathable and water proof keeping both wind and water out.

The Atom SV is designed to be worn as both an insulated mid layer or light outer garment in cold but dry climates.  As a stand-alone outer garment, the DWR treated Gossimer face is able to repel light rain and snow, but will quickly get saturated when subjected to rain or wet snow. The reason why Arcteryx did not use a Gore face fabric as they did on the Cold WX on their Atom SV is because unlike the Cold, the Atom was designed to be layered. One of the benefits of using a layering method as opposed to wearing a standalone insulated shell over the top of your base layer, is that you are able to easily add or subtract layers depending on your activity level or changes in temperatures.

On 3-4 day mountaineering treks I will typically pack 2-3 base layers, a light fleece, my Atom SV and my Alpha LT. When backpacking, pack weight is always a major consideration, so I  try and identify and eliminate any redundancy in my gear whenever I can. The Atom allows me to do this quite well, acting as both a light outer garment as well as an insulating layer underneath my hardshell when called for. I will usually start off wearing a UA Base or Marino Wool base layer, with my TAD Gear Ranger Jacket and then my Alpha LT over that. As I warm up, I will stop and take off my mid layer. I will throw on the Atom SV when I stop for lunch. Once back on the trail I will be back to just my base layer and Alpha LT, opening up the pit zips for a bit of venting and to help sweat and condensation to evaporate. Upon reaching base camp I will change into a fresh set of base layers and throw my Atom SV on and maybe my hard-shell if it is raining. For the amount of warmth it provides and the Atom SV is extremely compactable and regains loft very quickly. The Atom SV provides much more warmth, takes up less room in my pack than my Ranger fleece, and weighing a mere 11.5oz is less than half the weight as well. The nylon ripstop material is extremely breathable and the Tricot lining at the armpit adds further warmth and moisture wicking properties to the Atom SV.

The Atom SV is an ideal choice for times when you need more warmth than what the LT can provide and compliments the Alpha/Alpha LT perfectly when operating in cold/wet environments. Designed for military applications, the LEAF Atom SV is suitable for rotary wing aircraft or ground troop mobility, vehicle mounted and direct action tasks.  However, not specifically being a ‘Tactical’ jacket, and because of its resemblance to other civilian garments, it is not overly conspicuous making it adaptable to low vis work. The fit of the LEAF Atom SV will easily allow body armour and an OWB holster to be worn underneath without significant printing. Civi-side, the Atom LT makes a great choice for almost any winter activities; mountaineering, snowboarding, snowshoeing etc. not to mention for those frigid winter commutes, or while shovelling your driveway. Priced at around $259usd, the LEAF Atom SV comes in 3 subdued colors; Black, Crocodile and Wolf (shown here). Some of the other distinct features on the SV that are exclusive to LEAF are; the roomier fit, the vertically routed hem draw chords, the subdued deadbird logo, and the Velcro loop squares on the upper arms of the LEAF (*the LEAF Atom LT does not have this either).

Ultimately, the powers that be over at Arcteryx, decided that the Atom SV was redundant with the introduction of the Atom AR and pulled it from their civilian product line-up over 3 years ago at the same time they upgraded the Luminara face fabric on the LT to Gossomera. LEAF-side however, Deadbird only discontinued the Atom SV last year, based on feedback they received from their Military/LEO customers who wanted a more rugged, more wind resistant face fabric that would be suited for use in the sub zero temperature range. In 2016, Arcteryx introduced their Cold WX LT which is a part of their Cold Gear product line.

(Note: The Atom AR is essentially a varied fill version of the SV, using 120g of Coreloft in the body, 60g in the arms and 80g in the hood and is not offered in the LEAF line)

For my own needs however, I still prefer the Atom SV over the Cold WX if only for the fact that it can be worn both independently as well as under a designated hardshell. However if you are faced with sub zero temperatures with slim to no chance of heavy rain or wet snow in your area of operation, then the Cold WX LT/SV is going to be the way to go.

You can read our write-up on the LEAF Cold WX LT here.

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