Choosing A Mountain Jacket

Fabric Breathability's a bit of a red herring - you will, if you work hard, get hot and steamy in any jacket. The current most breathable is Gore's XCR but others aren't far behind and if breathability really matters, you can always opt for Paramo, though you pay a hefty weight penalty. Breathables work best when it's cold and dry outside and warm and humid within - bad in the UK, better for high altitude mountain work where the temperature humidity gradient drives moisture outwards. For mountain use, go for three-ply construction as it's lighter and more robust than the two-ply stuff which uses a drop liner to protect the fragile membrane from abrasion.

Venting Getting air to you is more important than breathability. New Mountain Hardwear research suggests that heads and forearms are the best areas to lose heat from - good news as rolling up sleeves and removing hats is free - and their new winter jacket has sleeve vents. Pit-zips and core vents work, but are really only effective when it's windy. Don't ignore the potential for opening cuffs out wide and unzipping the main zip either. If your pit zips are long, try sticking your entire arm through it for rapid cool down.

Zips Need a covering flap if they're going to be water resistant - Gore garments are constructed to certain specs meaning that they are, but look for a double flap over main zips and pockets if you expect to keep water out. Only exception are the new water resistant Eurotech zippers - YKK items treated with Urethane - which while not strictly waterproof won't leak under normal use. Chunky is good for main zips.

Fit Tends to get ignored, but the cut of a jacket is crucial. Needs to combine free movement with a close fit to prevent billowing when worn with a rucsac or climbing harness and the resulting flapping in the wind, 'I'm a sail' impersonations. A baggy climbing jacket will also stop you seeing your feet or racked gear on your harness. Things like articulated arms make a small but noticeable difference too. When trying, reach up overhead as if climbing and check the jacket doesn't ride up.

Drawstrings The best are housed in seperate channels to reduce rucking and abrasion of the main fabric and so they flow more smoothly and regularly. Avoid external cords which hand down in the centre of the waist area, they can tangle with belay devices and look a mess too. One-handed operation is a good thing.

Hoods A good hood is hard to find, or maybe a hard hood is good to find... Peaks for use in the UK need to be stiffened either by wire or some sort of laminate, without one they flop around in windy conditions, unless you wear a climbing helmet. Look for enough adjustment to pull the hood tight enough around your face and seal out draughts. Volume adjusters, normally on the back of the hood should shape the hood to fit combinations of head size and hats, as with cords, one-handed adjustment is good. The holy grail is a hood that fits well both with and without a helmet - few manage that trick.

Pockets Down to personal preference, but we prefer mesh-lined ones that don't reduce breathability and add bulk. If you're a climber, avoid hand-warmer pockets which will lie under a harness and if you use map pockets, check in the shop to make sure an OS map fits properly. Some expedition jackets have internal waterbottles to stop your water from freezing.

Neck Area To much Velcro, zip and flaps can make the neck area stiff and uncomfortable. Be wary of fleece-lined chin guards too. In really savage conditions they can become saturated with water and then freeze solid. Ouch, chin meets sheet ice.

Water Repellancy When jackets are new they're impreganted with a surface treatment that stops the face fabric from absorbing water and impairing breathing. With use these wear off causing the jacket's surface to absorb water, the membrane stops breathing and you get damp from condensation. You can reproof the jacket using specialist treatments - see this article for details.

Wear Areas The classic areas for reinforcement are shoulders - wear from straps - and forearms - from abrasion - and you should look for a tougher fabric in these areas. On top of this, long term wear also hits drawcords where they don't run in a seperate channel as the fabric rucks along the cord then abrades, and cuffs. Better jackets will also be reinforced in these areas.

Credibility There's a tendency to over-specify kit in the UK. No-one's saying you can't wear a top line alpine jacket for walking the dog, but don't think that you have to. There are plenty of more than adequate jackets around in the sub-200 quid bracket and some passable ones for under £100. Sure, you won't get as many features and breathability may be down on the top stuff, but it'll still so the job and in the end it's you who has to climb the mountain, not your jacket...

Breathability A bit more on breathability. Most membranes and coatings work in a broadly similar way in that they keep the water out, but allow water in the form of vapour to permeate through from inside. All work best when there's a positive temperature humidity gradient between the inside and the outside, which will help drive water outwards. So hot and humid inside and very dry and cold outside is where they work best, ideal for high mountains. Unfortunately British conditions tend towards the damp, making them more demanding for breathables.

You can help things by wearing only wicking fabrics below the outer shell layer. Proper base layers and a thin fleece should be enough. Cotton tee-shirts simply absorb sweat and hold it close to the skin stopping your outer layer from working properly.

The other major factor governing breathability in wet conditions is the water repellancy of the surface fabric. If water soaks into the fabric, the breathablity drops and you get damp from condensation on the inside of the jacket.

Weight Light is easy enough, but light, tough and breathable is more difficulate to achieve and means that many cheaper jackets though capable, are very heavy. Somewhere between 800 and 1000 grammes is reasonable and about par for the course, but topline jackets can and should be lighter. Bear in mind though that very light fabric is likely to be less durable in the longer term.