Clothing Layering Strategies
The benefits with layering clothing in the outdoors is well known. The traditional approach of the 3 layers (base, mid and outer) assume that conditions and level of activity will remain relatively constant during the course of the day. With alpine climbing, particularly in New Zealand, we know this can be far from the case and an alternative layering approach is required.
The Outer Layer is the most important. This is the outermost layer that you anticipate using for the majority of the day. When choosing a garment for this it you need to take into account required weather proofness versus level of activity (how much heat you are going to generate) and durability versus weight. There will always be a compromise. Busting through the bush or on the rough Darrans rock you might want to sacrifice some weight for durability, otherwise you might soon end up with a lot of patches. Waterproofness is not as important unless you are planning to be spending lots of time in the rain. Similarly in winter when it will hopefully be snowing rather than raining. The key is staying comfortable and being able to adjust your temperature without stopping too often take on and off layers, especially under layers.
As conditions change during the day you need to be able to quickly adjust. Sometimes this can be achieved using zips, changing gloves or beanies. Otherwise this is where the Over Layer comes in. his is a layer to add warmth or additional weather proofness for shorter durations of the day. For example cold, pre-dawn starts, breaks, belays or passing showers. This will generally be slightly oversized to fit over your Outer Layer and a full length zip for quick changes. As this layer is an occasional item, durability isn't as important but weight and packability is, it will spend plenty of time in your backpack.
When choosing garments, materials are obviously important and well documented. Fit and function are as important. Technical clothing manufacturers such as Rab actually specify the fit of each garment (slim regular and expedition fit) taking into account layering principles. Avoid bulk in high movement areas (like arms) and choose materials that move well next to each other to maximise your freedom of movement. For example fleece tends to ‘stick’ to other fleece layers but fine weaved nylons slide well over fleeces. Too many hoods can get congested around the neck and head. Under helmet hoods are best reserved for mid layers and over helmet hoods work best Outer and Over Layers. Generally thumb loops and elasticated cuffs work well for under layers and Outer Layers. Good insulation around the wrist, where the blood vessels are close to the surface, will help keep you hands warm but too many tight cuffs will be uncomfortable. Wide velcro adjustable cuffs are good for Overs Layers and work well with bigger outer gloves.
So taking all this into account my almost all season Outer Layer is a windproof and water resistant jacket like the Rab Vapour Rise. In colder conditions I may go for a softshell but otherwise these are too bulky and less breathable. For Over Layers in cold dry conditions go for a synthetic fill jacket or vest or a lightweight waterproof for rain protection.