Imagine this: You boot up for a backcountry skiing or snowboarding ridge tour in cold, gusty winds. At the top of the thigh-busting skin-track, you’re sweating bullets. Here, you switch gears and point em’ downhill to mow fresh lines in waist-deep powder. Despite working up a lot of heat on the ascent, now the chilling winds have you feeling even colder than before.The highly dynamic nature of outdoor activities is the raison d’être for fabric technologies. A 20-mile per hour wind at 41 degrees will feel like 17 degrees in two minutes.
“Even small fluctuations in internal temperature matter in your clothing system,” says Dan Cauthorn, account manager at GORE®, a leading manufacturer of performance fabrics.
So how do you manage these two competing issues of external and internal conditions?
Outdoor Research uses GORE®’s WINDSTOPPER® fabric to address this question in many of its technical pieces. This highly dynamic layer breathes, allowing moisture and sweat to escape (keeping you dry), while blocking cold winds from entering. But to fully understand how WINDSTOPPER® works, take a look at its parts.
WINDSTOPPER® is a laminate, which means it is sandwiched together with other textile layers to create a single fabric. The first layer is the WINDSTOPPER® membrane. This ePTFE (expanded polytetrafluorethylene) film is a megalight, incredibly versatile polymer that has 1.4 billion micropores in a single square inch of the membrane. These micropores are 900 times larger than water vapor molecules, which allows water vapors to escape nearly unhindered. The ePTFE film is the most basic part of WINDSTOPPER®; but it’s performance features are enhanced by what’s stuck on one or both sides of it. The ePTFE membrane is bonded to another fabric (often a nylon face) and, in some applications, a third against-the-skin layer. The result is a windproof fabric that is highly breathable.
While WINDSTOPPER® is windproof, highly breathable and water resistant, it is not waterproof. GORE-TEX®, like WINDSTOPPER®, is a laminate, but the difference is the GORE-TEX® membrane has much smaller pores, with over nine billion pores per square inch. The smaller pores completely prevent moisture from penetrating from the outside, making GORE-TEX® fully waterproof and windproof, but less breathable than WINDSTOPPER®.
Here at Outdoor Research, we use WINDSTOPPER® in a few of different ways. First, we use WINSTOPPER® in some of our insulated jackets. For example, our men’s and women’s Havoc Jacket™ is made with a two-layer WINDSTOPPER®, making it ideal as an outer- or midlayer in cold, wet and windy conditions encountered while alpine climbing or backcountry skiing.
“The Havoc keeps the wind from stealing precious warmth and energy on climbs,” says Nik Berry, Outdoor Research Climbing Ambassador. The Havoc is his go-to jacket high on the granite walls of Yosemite National Park.
The second application that we use is WINDSTOPPER® soft shell, which is found in our Valhalla Jacket™ and Pants, Salvo Beanie™, Mixalot Gloves™ and Stormtracker Gloves™. WINDSTOPPER® soft shell is a three-layer fabric – the ePTFE membrane is bonded with a nylon stretch woven face and a backer made from a lightweight yet warm brushed knit.
“What makes this soft shell unique is that it’s totally windproof without losing breathability,” says Cauthourn. “It excels in especially cold aerobic activities like randonee skiing, ice climbing or mountaineering.”
The mega-stretchy nylon fabric allows uninhibited movement while maintaining supreme protection in a wide range of temperatures.
Outdoor Research also uses a three-layer WINDSTOPPER® technical fleece, which has an ultralight WINDSTOPPER® membrane sandwiched between two fleece materials. We use this technical fleece in styles including our Wintertrek Hat™, Spitsbergen Hat™, and Gripper Gloves™. The technical fleece is ideal for activities like running or backpacking in cool, but not cold, conditions as a mid- or outer layer.