The biggest dirty little secret in the outdoor industry is that waterproof/breathable rain jackets won’t keep you dry and will wet out. It doesn’t matter if you buy a high-end $450 Arcteryx Gore-tex Parka or wear your bathrobe, they’ll both Wet Out in continuous rain and leave you soaking wet.
What is Wet Out?
Most 2-layer or 3 -layer waterproof/breathable rain jackets and pants are coated with a Durable Water Repellent (DWR) finish that makes water bead up and roll off without saturating the exterior fabric. The breathable layer is often sandwiched under or between two fabrics that protect it or provide a second surface that moisture can evaporate from. Wet Out occurs when the external DWR coating wears off, the jacket’s outer fabric becomes saturated and prevents the internal membrane from passing out water vapor.
This is a good reason to maintain your DWR layer regularly by washing your rain garments and reapplying a DWR conditioner like Nikwax TX-Direct Spray-on Water Repellent Treatment to restore it, but it doesn’t change the fact that the DWR coating will rub off quickly, particularly on your shoulders where your backpack shoulder straps rub it off. It’s less of an issue for runners and downhill skiers because they don’t wear backpacks like hikers.
Wet Out Mitigation Strategies
If your rain gear starts to wet out, you run the risk of getting chilled or even hypothermic in cooler weather. Here are a couple of things you can do to mitigate this risk and still keep hiking.
- Hike faster, keep eating and drinking to keep your core temperature up. Dehydration can accelerate the onset of hypothermia, so keep drinking even if you don’t feel thirsty.
- Put on additional base and mid-layers. While these may eventually become saturated, additional layers will help you retain more body heat. They will also disrupt the transfer of cold from the surface of your jacket or pants to your skin. Your layering system should work to keep the layer against your skin dry and move moisture away from your skin.
- If you have pit zips on your jacket, open them to help vent moisture. Pit zips are underrated in this era of breathable, waterproof garments.
- If you can’t stay warm, set up a shelter and get into your sleeping bag to warm up. It will stop raining eventually.