Heli Ski Equipment: Waterproofs
Recently we’ve had a look at what contributes to making an excellent outer jacket for your next heli-skiing holiday. But whilst browsing what new jacket or pants to get for this or next season, you may, like many others, have come across numbers in the tech list that mean nothing to you whatsoever. These numbers such as 10,000mm, or 20K, relate to the rate of waterproofing of each jacket.
At first you may think there can’t be ‘levels’ of waterproofing, it either is or isn’t, you either get wet or you don’t. Actually, the majority of outer jackets are just very, very water resistant. Examples of materials that actually are entirely waterproof would be thick rubber (used by deep sea fishermen), and metals used to construct boats. The trouble is with the first example is that it has little or no breathability at all. Try snowboarding in a fishermen’s getup and you’ll soon be soaked through, not from the snow but from all the perspiration you’ve generated that has nowhere to escape.
Most companies who produce these jackets generally use two methods of testing the “waterproofing” that certain materials provide. The first is rain room endurance tests. This is really to meet international customs requirements, and whilst it may provide some data, has no real scientific measurement, and so doesn’t relate to the numbers we’re concerned about.
The second test is known as static column water resistance, and this is the source of these unidentifiable ratings. A 1-inch diameter tube is securely placed vertically over a test piece of the fabric. Water is then applied into the tube, and at the point when this water starts to permeate the fabric the height of the water is recorded. This height is recorded and published to the public as the waterproof rating.
So an extremely good waterproof rating may be as high as 25 – 30,000mm, whereas some garment that only manages 1000mm – 5000mm may resist water but will allow penetration after continual exposure to moisture (i.e. when sitting in wet snow for a prolonged period).
As to whether these measurements directly relate to the jackets’ overall real-life performance is a point of contention. Other factors often have to be considered, most importantly the amount and type of seam waterproofing, and how much breathability you require from your outerwear. Also companies may, intentionally or unintentionally, vary the methods of their tests – there is no standard to be adhered to – therefore after washing or continual use, you could never be sure how the gear will perform. GoreTex, for example, actually never even release their test results, relying on their reputation, and guaranteed waterproof and breathability effectiveness.
So now you know. We’d suggest a balance between waterproofing and breathability, as well as getting a good fit to your other layers – don’t expect your jacket to breath much if you’ve three layers of windstopping fleece underneath!
Tags: Heli Skiing, Heliskiing, Heli Ski, Heliski, Heli Skiing Tour, Heli Skiing Holiday, Heli Skiing BC, Heli Skiing Resorts, Heli Skiing Lodges