Your ski jacket is waterproof. Or is it? And what does “waterproof” even mean, and how does a jacket being “waterproof” or not impact your skiing?
All excellent questions. You might think that it is a given that your ski jacket is super waterproof, as it rains and snow when in the mountains, and you need the protection to keep you dry. But actually, it doesn’t rain or snow that much comparatively, meaning that you might not need a fully waterproof set up.
In this piece, I explore what it means for a jacket to be “waterproof”, and why not having a waterproof jacket might be expected, as well as any other protection you might have against the elements.
What is “Waterproof”?
In many ways, this is a really simple question to answer; it is any material that stops water soaking through without any adulteration or additional protection.
However, there is a legal definition, as well, and that can help us define things that aren’t waterproof as much as things that are. According to British law, to be considered waterproof, a jacket or waterproof trousers must meet the following criteria:
Waterproof material – the material the jacket is made of must be waterproof itself. In lab tests, a square metre of material, without any adulterations or additions, must be able to support a column of water at least 1,600mm3 without leaking for a period of 24hrs.
Taped seams – the stitching of your jacket or trousers is an inherent weak point as you are punching hundreds of holes in the waterproof material. Therefore, seams must be backed by seam tape of a sufficient width to fully cover the seam and prevent leaking.
Sealed zips – similarly, zips on a piece of waterproof clothing are weak points. They must be sealed or have a flap acting as a physical barrier to withstand water.
You can achieve waterproof by a variety of different methods, but almost all ski brands choose to laminate a waterproof membrane between two layers of fabric – known as the face fabric on the outside and a liner on the inside. This was a designed pioneered by Gore-Tex, who created the world’s first membrane that was still breathable, i.e. it still allowed sweat vapour to pass through whilst keeping rain and water out. Overtime, many brands have copied this technology into their own versions, but Gore-Tex remains as the best waterproof & breathable membrane on the market.
Is ”Waterproof” Essential for Skiing?
There’s not really an easy answer to this one. If you were to blindfold yourself, walk into a ski shop and randomly pick a jacket, probably about 90% of the jackets on sale would be waterproof. The remaining 10%, particularly women’s jackets, are more likely to be “water resistant” (see below).
Despite your first assumptions, it doesn’t rain that much in the mountains, and snow impacts – literally – your jacket far more gently than rain does. Therefore, having a fully waterproof jacket may not be essential for your skiing adventure.
Salomon have understood, and now roll out almost their entire range of jackets with a “hydrostatic head” of around 10,000mm3 – this is the test carried out in point 1 of the legal definition of “waterproof”. This is around a quarter of what Gore-Text roll with, and half of what I would personally consider to be a “good” level of waterproofing (able to withstand prolongued heavy rain). But they know you don’t need the same level of weather protection, susceptible only to snow and the occasional rain, that you are going to run to the nearest café or bar to avoid!
There are other reasons, too. Waterproof materials are almost always heavy, so if you have a jacket featuring down insulation, you may avoid waterproof materials to reduce the pressure on the down insulation packed into the jacket.
Similarly, when you ski, you generate a lot of heat and sweat. Remember how I mentioned that Gore-Tex was the best material that was still breathable? Well, it’s all relative: you need a difference in heat and humidity, and when you are sweating buckets any barrier will limit breathability, especially as Gore-Tex and other membranes remain simple sheets of plastic. The most breathable material is nothing, but obviously you can’t wear just that (well you can, but it’ll be cold …)!
Therefore, a non-waterproof – but still water-resistant layer might be better. You’ll often get this with touring jackets, such as the Rab Khroma I reviewed last season. Especially for longer ski tours in occasionally bad weather, a water-resistant jacket will do its best to keep you dry but allow sweat vapour to pass through.
At the same time, jackets designed for serious skiing in at times serious weather conditions will go the whole hog. Most jackets designed for backcountry skiing will be completely waterproof, as showering snow from that awesome face-shot turn you just pulled will need to be kept off you. You will also be skiing in worse conditions, and not making a run for the bar or café when it turns to rain – at least speaking from experience!
The top end jackets from the top end brands – Arc’Teryx. Norrona, Haglofs, Ortovox and even The North Face – that are designed for staying out and skiing in all conditions, utilise Gore-Tex and very tough face fabrics, designed to protect you from the worst of all conditions.
A Note on DWR
A Durable Water Repellent (DWR) coating is applied to all waterproof jacket, and forces water to bead and roll off the face fabric. It is also applied to plenty of non-waterproof jackets – this is what makes a jacket “water resistant”, the material itself is not waterproof, but the DWR coating on it provides some layer of weather protection. On waterproof jackets, it acts as a secondary layer to the waterproof membrane, helping protect the face fabric extending its lifespan and improving its effectiveness at keeping water off the membrane underneath.
DWR is not permanent. It is a chemical coating that will wear off in time and with more use. You should expect to replace it every little while in order for it to be effective – this can be done quickly and easily via spray on or wash-in solutions and can actually be an improvement on the factory finish your jacket is delivered with.
More and more brands are switching to a more environmentally friendly DWR solution, as traditional DWR chemicals have a lot of “forever chemicals” or PFAS, chemical solutions that are unnatural and never degrade in nature. This is undoubtedly a step to be celebrated but note that the new green DWRs are … terrible. They do their job fine but wear off the jacket in no time at all. Therefore, if you purchase a jacket with a new, green DWR coating, be aware that you will need to re-coat it with DWR more regularly than you did previously.
Final Thoughts
There is a strict definition behind what “waterproof” means, but don’t let this tie you in knots. Unless you are looking for a hardcore all weather all mountain gnarly ski jacket, you can get away with a lower level of waterproofing or even simple water resistance.
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