Breathable Waterproof Ski Jackets

If you ever wondered how to sort through the maze of different ski jackets, cut through the hype, brand names, this article may help. We will condense attributes of ski jackets into components, namely breathibility and water resistance. We will try to help demystify the two terms. Lets start with jacket waterproof characteristics first.

In my mind a truly waterproof fabric is one which does not allow water penetration at all. Irrespectively of the degree of water pressure applied, it will not leak. The reality is however the textile industry has got a different definition. For a fabric to be classified as waterproof it needs to withstand water pressure applied from a 1m high column, and not leak. (Some countries feel 1.5 should be the cut off point).

This approach tests the fabric’s resistance to water penetration. If the fabric withstands water pressure applied from a 1m ,1000mm (or approx 4 feet ) water column, it is said to have a “hydrostatic head of 1".If the fabric withstands water pressure applied by a 2m water column, it has a “Hydrostatic Head of 2".So to follow on, the fabric or a jacket will have a better water-proof ness if it has a water head reading of 2 , rather than 1.

How is this relevant to skiing?

Being exposed to a blizzard, heavy snow , hail and rain, wearing jackets with low hydrostatic head reading will allow them to become wet and porous very quickly. The jackets, which have higher hydrostatic head rating will withstand the blizzard better. This is because the fabric can withstand higher water pressure. Think of this analogy as ,someone sprinkling you with water, as opposed to you being hosed under high pressure. What sort of weather are you ready for?

Our four way approach of choosing waterproof ness of a “waterproof jacket"

• 1/ If you are venturing well beyond ski patrolled boundaries ,going into extreme blizzard weather, consider a breathable waterproof jacket with a hydrostatic head rating of 20 plus ( 20,000mm).
  
• 2/ If you are reasonably close to civilization, and may be able to find shelter from extreme climactic conditions, should a blizzard arise ,than 10 hydrostatic rating is sufficient.
  
• 3/ If you are looking for a breathable waterproof jacket that offers some versatility and does not break the bank account, consider rating 8. 4/ For most of us skiing in patrolled areas, without the weather being too uncomfortable, clear shiny days ,a hydrostatic head rating of 3 should be sufficient.

Now let’s venture into jackets breathable characteristics.

Why is it important to have a jacket which breathes?

All the perspiration that accumulates under the outer wear ,or any part of your waterproof breathable jacket or garment will condense. Continual condensation will cause fluid build up until soon your inner insulating layers become wet. If you are wet ,you’ll become cold very quickly. So whilst you want the jacket to shield from the external elements, your own perspiration can be your enemy. Internal fibres should be designed in such a way as to whisk moisture away from your body to the outside of the jacket. In doing so you will stay dry, and in shape to take on your next ski challenge.

Measurement of Breathibility.

In testing ski fabrics one needs to calculate the rate at which fluid is whisked away from your body. Three variables are computed, the weight , the surface area, and time. One outcome is a mathematical figure which tells us how many grams of water vapour have diffused, or passed through a 1 m2 of fabric in the time of 24 hours .In other words how much in this case vapour will pass through a section of a fabric in 24 hours. An example of such a figure is quoted as i.e. 10,000 gm / m2/ 24hrs. To follow on this point a jacket which has figures of 10,000 gm/ m2/24hrs breaths better than a jacket which quotes 5,000 gm/m2//24hrs.

For recreational use chose fabrics with minimum breathibility as shown above. Be mindful however, that a breathable waterproof jacket which has a very high waterproof rating of 20 plus, or even 45, being usually triple layered ,will not attain a very high breathibility, usually less than 12,000 gm / m2 / 24hrs.

Another figure which measures the outcome of performing the above testing , is the RET figure (resistance of evaporation of a textile).Think of this figure as being related to the above quoted one in that the better the fabric breathes the less resistance it has. This figure is quoted as i.e. RET= 60. Since we measure resistance, the less resistance we have the better. So RET = 60 has better breathibility than RET =90.You may find one manufacturer may quote you an RET value whereas another gm/m2/24hrs.

Regards

Christopher from www.ski-adventure-guide.com

BIOGRAPHY

We have travelled the world on our quest for snow. As a result have covered quite few countries and continents and would like to share our experiences with you. A personal look at ski travel and adventures that follow.