Backcountry Test: Polartec 'Alpha' Jackets (in Tetons With Exum Mountain Guides)

All photos courtesy

Last year, Polartec introduced its Alpha insulation for jackets. The synthetic insulation, which has military roots, is unique because it offers breathability as well as warmth, including in “puffy”-style jackets. (We preview Alpha in our article “Military-Spec Jacket Material soon available to Masses.”)

A number of brands introduced outerwear using Polartec Alpha this past season. But one company, Marmot, embraced the material more than others, and it has gone to great lengths in testing and proving Alpha’s mettle.

I got an inside look at the testing process with Marmot and one of its partners, Exum Mountain Guides. After a 4,000-foot-vertical hike, a short rappel, and a two-hour ski out, I was beginning to see the Alpha light.

Exum guides test Marmot jackets with Polartec Alpha outerwear

Marmot, which just turned 40 years old as a brand, has been working with Jackson, Wyo.-based Exum for two decades. Over my three-day trip, the guides and I wore identical Marmot-Polartec outerwear pieces (a breakdown of each is on Page 2).

“Alpha is one of those technologies that creates a whole new class of products that previously did not exist,” said Marmot outerwear category manager Brian LaPlante as we slogged skin track to the top of Turkey Chute. “I equate it to when softshells came into the market.”

Exertion on a 4,000-vert climb in the Tetons

LaPlante said that just like softshell jackets Alpha has the potential to make people “reevaluate the clothing we were wearing and how we were using it.” He continued, “Alpha is forcing us to rethink our traditional clothing systems” for the outdoors.

What’s all the fuss about? In short, Alpha is warm. But it’s also breathable and air-permeable. These attributes do not often piggyback each other — warm jackets are usually clammy, and breathable jackets offer little warmth.

At GearJunkie, we’ve tested multiple Alpha jackets. We agree with the hype — the airy insulation keeps body heat in check while also letting moisture escape when you sweat.

Nearing the summit on test day

Alpha insulation is described by Polartec as an open-knit, high-loft fleece. Its main competition is goose down and other synthetic insulation like PrimaLoft.

But Alpha is like an airy fleece, not a loose insulation fill. As we noted in the initial review last year, “down feathers and most synthetic insulation can poke through permeable fabric. This means puffy jackets often use dense materials to encapsulate the insulation, creating jackets that may not let sweat and body-heat moisture easily escape. [But] Alpha enables the industry’s first breathable puffy garments — the fleecy Alpha material is an insulating mass that traps body heat, but it is also stable enough to be stitched into jackets that use highly-breathable fabrics.”

In Wyoming, I skied next to Allon Cohne, a marketing director at Polartec. He’s paid to be excited about Alpha, but under that I could see his trust and enthusiasm in the product. He noted, “Most protective insulation is great for static uses like standing around or walking, but when you’re [on the move] you don’t have time for layering.”

Polartec first made Alpha for the military. Special Forces tested the in-development product in Alaska where they would “soak it and walk it dry,” Cohne told me.

The story goes, soldiers were ordered into a river for five minutes to soak. The Polartec product wasn’t the only fabric being tested; there were several different fabrics in the water. Once soldiers were soaked, they were ordered to “walk their garments dry,” which meant hiking in the cold while dripping wet.

The idea behind this test was that body temp will dry the fabric out eventually. Polartec Alpha not only passed the test and beat the competition, it was reported to be one of the best Special Forces products ever tested, Cohne said.

On my backcountry trip there was no required “soak.” But I tested Alpha to my limits — skinning uphill for hours, drenched in sweat. I stayed warm even when wet. Also, exertion did seem to help dry the insulation — when I got warm my body heat “pushed” the moisture out more than with any other jacket I’ve worn. See page 2 for the full breakdown on my Marmot/Polartec kit. —Aaron Bible

Tall peaks in the distance, heading home