Not all waterproofing technology is created equally. The secret to staying dry, warm, and comfortable on the mountain comes down to three distinct features.

1. DWR Treatment

When you watch water bead off your jacket rather than sink into the fabric, you’re witnessing durable water repellent (DWR) in action. DWR is a water-resistant coating that’s applied to outerwear fabrics to prevent garments from “wetting out”—a term that aptly describes what happens when your jacket soaks through and instantly loses its breathability and insulation properties.

In addition to repelling falling rain and snow, DWR is the first line of defense against moisture that’s applied with pressure. When you’re sitting on a lift, your entire body weight is pressing against the chair and pushing moisture into your ski pants and jacket. DWR is designed to stand up to this extreme pressure and prevent water from penetrating into the fibers of the fabric.

DWR is often applied to fabrics that have been specially designed or treated to be water-resistant. These fabrics are the specialty of industry-acclaimed brands like Gore-Tex, but the same technology is also available in non-branded forms.

2. Waterproof Membranes

If DWR is the first line of defense against moisture, waterproof membranes are the second string. Without this thin, plastic-like film, a garment may be water-resistant, but it won’t be truly waterproof.

Membranes are typically used in performance outerwear in three ways:

• As an outer shell: Waterproof membranes can be laminated and applied to the outermost layer of a garment, creating a hard shell.

• As an inner layer: When placed between the insulation and the outermost layer of fabric, waterproof membranes stop moisture from seeping into the insulation layer.

• As a liner: A waterproof membrane prevents water vapor like sweat from penetrating the garment from the inside out.

Together with DWR, this three-level membrane combination provides the highest degree of waterproofing possible for high-performance outerwear.

PTFE

Although waterproof membranes are intended to keep you dry, some types are known to hinder breathability. If you find yourself zipping and unzipping your jacket as you break a sweat on the hill, then your outerwear membrane probably isn’t made of polytetrafluoroethylene (PTFE).

PTFE is the most advanced waterproof membrane on the market. Unlike its predecessors, PTFE is exceptionally thin, flexible, and porous. The pores are small enough to prevent liquid like melting snow, sleet, and rain from penetrating the membrane, but big enough to allow water vapor (i.e., sweat) to escape. Because PTFE doesn’t require additional lamination as an outer layer, it’s also exceptionally breathable, flexible, and light.

3. Seam Sealing

On a basic level, the more tiny holes that exist where the fabric has been sewn together, the more opportunities exist for moisture to pass through.

To eliminate this risk, garment seams can be reinforced with a sealant or seam tape. Oftentimes, only the critical seams (areas that are most vulnerable to moisture penetration) will be sealed. On a jacket, critical seams include the shoulder, armhold, and hood back yoke. For pants, critical seams usually refer to the knees, ankles, and rise.

Down

Down is typically made of duck or geese feathers and is known for being extremely warm, lightweight, and compressible. If down gets wet, however, it instantly loses all its insulation properties. To remedy this risk, down can be treated with DWR to heighten its water-resistant properties. DownTek is an example of a DWR-treated down brand.

Down jackets will typically be given a power and a weight rating. Power refers to the resistance of the feather to pressure. Higher-quality down that uses fewer quills and more plume will have a higher power rating. It will also provide more loft with less fill.

Weight refers to the amount of fill used in the garment. Together, the weight of a garment and the quality of the down impact its warmth, compressibility, and breathability.

Synthetic Insulation

There are two main types of synthetic insulation available: rolled and blown. Rolled insulation is more common due to the fact that it’s cheaper and naturally more water-resistant than down or blown synthetic alternatives. That said, rolled goods don’t stretch or flex well. They also tend to be dense, heavy, and stuffy.

In contrast, blown synthetic insulation is much less dense, allowing more air and water vapor to permeate through the garment. Blown insulation offers superior stretch and flexibility, improving your range of movement on the hill. To achieve two- or four-way stretch in an outerwear garment, using blown insulation or a down/synthetic blown blend is a must. PrimaLoft is a well-known synthetic blown insulation brand that offers both a synthetic down blend (half down, half blown synthetic) and a fully synthetic down (100 percent blown insulation).

In addition to the type of insulation used, there are a handful of other factors that dictate how warm you feel in your outerwear, including:

• Waterproofing and breathability

• The amount of insulation used

• Layering (what you wear underneath between your skin and your outermost layer)

• Seams (whether or not they’re sealed)

• Garment care

Dirt and oil can get into the pores of outerwear fabric, affecting its breathability and abrading the DWR treatment. To ensure your gear continues to perform up to par each season, make sure you’re giving it the right kind of TLC. Follow the care instructions included on the tag!