WATERPROOF SKI JACKETS
Ski jackets are waterproof by their nature - they have to be to operate in snow and powder. However, waterproof is a linear measure, not an absolute term. Waterproofing is measured in millimetres, representing the height of a column of water 1-inch wide that can be poured onto the garment without water ingress (static column water resistance test). So the higher the number, the more waterproof performance you can expect. Here is a quick breakdown of levels of waterproofing :-
- 1500mm- 5000mm - rainproof but not waterproof under pressure - if you lean into a snow drift you will eventually get wet - think entry-level skiwear. Perfect for beginners if you are not sure you are going to fall in love with skiing, so want to keep the costs down.
- 5000mm - 15000mm - totally rainproof and decent waterproofing under pressure - you can sit on the piste for a long, long time before there is any chance of getting wet. Perfect of intermediate skiers where you might try a bit of off-piste and backcountry skiing.
- 15000mm - 30000mm - waterproof even under pressure - Gore-Tex and eVent and other PU laminates and PTFE membranes. This will likely keep you dry in low pressure water submersion.
- 30000mm plus - totally waterproof and impermeable - Perfect for the pro- cross-check with its breathability rating because unless this is also moderate to good you might get a bit sweaty!
BREATHABLE SKI JACKETS
A waterproof ski jacket is only useful to you if it is breathable too. Water vapour and sweat need to escape, so a decent level of breathability is recommended. This is especially true if you are a more advance skier and will be working hard in mogul fields or off-piste powder.
Breathability is generally measured by the formula g/m²/24h - meaning the grams of water passing through a square meter of fabric in 24 hours. This is also often expressed as MVP (moisture vapour perspiration) but it is the same measurement. So higher ratings mean they are more breathable ski jackets.
Unfortunately the is no universally excepted testing regime for rating breathability, so comparing manufacturers ratings can be less than fruitful. However, do gauge ski jackets against each other from the same brand as they will have undergone the same testing criteria within the brand’s testing laboratories. Here is a quick indicative scale of breathability :-
- 0 g/m²/24h - not breathable at all
- 0 g/m²/24h - 2000 g/m²/24h - moderate breathability, suitable if you are not going to be too active. Think après ski.
- 2000 g/m²/24h - 5000 g/m²/24h - decent breathability, suitable for less strenuous activities - think gentle carving on blue and green groomed piste.
- 5000 g/m²/24h - 15000 g/m²/24h - good breathability, suitable for moderate activity - think fast on-piste skiing on reds and blacks.
- 15000 g/m²/24h - 30000 g/m²/24h -excellent breathability, suitable for very strenuous activities where you are definitely going to sweat a lot - think off-piste, deep powder and mogul fields.
- 30000 g/m²/24h plus - this is top end performance and is suitable for winter athletes and the serious skiers working at the limit where compromise is not an option.