The "extra clothing" is the clothing items you carry because the weather may change.This may be as simple as one change of warm and dry socks.

For example, you became disoriented, or lost, easily engulfed in fog because you are near the seashore or the mountains are at the height of the clouds.

The wind came up, the rain fell. It snowed.

If you do not have extra clothing, you are at risk.

Most hypothermia deaths occur in mild weather: wet and chilled, from failure to stay dry from outside, or from sweat on the inside clothing, or from failure to get warmed up, than from the extreme cold.

While still necessary to dress in layers for outdoor activities, the layers are thinner, more flexible, and less bulky than their counterparts.

The newest fabrics offered now allow using one reasonably lightweight, or ultralightweight item of clothing to accomplish what needed two, or even three layers not so long ago.

Some of the newest excellent fabrics and the oldest natural fabrics, now modified, based on the modern principles of dressing in layers, catenary cut clothing with provision for ventilation are not uncomfortable, heavy nor bulky to wear.

It is possible to "walk dry" your clothing: I have done it, with no special exertion. A lightweight inner layer pushes moisture to a highly evaporative protective outer layer.

If I wear any inner layer at all over underwear, I like to wear a silk or silk blend inner layer, to retain some "insensible moisture" on the skin surface, because it has been shown we will continue to pump out moisture to provide that "insensible moisture" on the skin, and without it, for example wearing a drying inner clothing layer our skin will become dry, chapped and other not good things for skin. Our skin is our first line of protection. I protect it.

Next, I have a protective wind and water repellant, not film fabric. Natural oils and ordinary dirt clog film coated fabrics, and extra layers of fabric have been added to protect that film, adding more weight to the garments made with this stuff.

Note: Waterproof is for inactivity. Otherwise, water shedding properties are more desireable.

I have better success, at finding windproof and water repellant qualities desired, with the newest fabric offerings to the public that have a weave or some technology that has been integrated in the fabric weave, or layers of "one cloth" or in the actual fibers of the fabric.

While it is possible to retreat DWR treated clothing, I have included only a few DWR treated clothing items in the listings at Products. I wear DWR treated specialty lightweight and ultralight backpacking clothing, but I clean and re-treat the DWR using Nikwax products. If you want to, do clean and re-treat with Nikwax brand product.

I rely, instead, on an inner layer having a half-zip front of warmth selected for reasonable expectation of the weather conditions, and a water-repellant half-zip or full front zip "windshirt", and a poncho. Most people would not opt for a poncho, although The Packa pack-poncho has been making headway with the public.

Most people add a jacket on their back, or in their pack.

If you do, have the most ventilation possible built-in as a feature of that jacket: full zip front, pit-zips, front opening mesh pockets, and wrist closures that will open. One jacket design has open-weave panels down each side for ventilation. I have a specialty mountaineering jacket, with a hood that has "chimney ventilaion" for ventilation for exertion, while wearing the hood. Nice.

Other people prefer to carry the lightweight and not necessarily durable rainsuits I have listed at Products.

I happen to think a fitted and also generously proportioned poncho-tarp is universal, for rain, for shelter, and wind. Most people do not agree.

It isn't fashionable.

I was glad I had "my" fashionable alpaca poncho wrap one cold night in the mountains of southwestern Oregon.

I once gave my best long Kelty rain poncho and Black's of Hawick Scotland "scots" double twist and double weight, double thick heel, wool socks to an ambitious, if young, world traveler. I got a postcard, from Sardinia, how happy and grateful he was for these useful gifts. Nowadays, I keep my poncho tarp in the waistpack, that can be worn around in front, the poncho ready to spring into action.

There is ultralight backpacking, using an ultralight umbrella from GoLite or Mont Bell. Me? I would combine the ultralight umbrella, with one of the other wind and rain solutions I have mentioned here.

If your regular clothing is all cotton, nothing I can offer here will help much. In particular, blue jeans hold onto the wet.

Unless the you have the justifiably famous all cotton British Ventile cloth outerwear, which is superior, do not wear cotton for hiking, backpacking, mountaineering or trekking.

The new fabrics are recommended with few exceptions, and some older fabrics are recommmended: including the great fibers of silk, wool, rayon or nylon that are comfortable to wear and are not going to ruin your trip.

If you regularly wear quick drying travel clothing, planned extra clothing is all the more beneficial.

Do not allow the inner layer of clothing to become soaked, from outside moisture like rain, or from sweat. Regulate your activity: slow down. Open up your clothing: open the cuffs, pull out shirttails, open the collar, open some buttons, open the garment altogether, remove outer garments and carry on your arm, not tying around your waist, reducing ventilation more. Wear suspenders. Open up your pants. No one is around. If no suspenders, maybe long shirttails or a long jacket will cover your open pants. It is that important, do not soak your clothing with your own perspiration.

There is outer and inner layer clothing that you can "walk dry": warmth comes from inside you. The clothing you wear only holds that warmth, by insulation and/or windproof or water resistant qualities. Do you have any "walk dry" clothing? A lightweight inner layer and nylon supplex trousers, for example, will "walk dry".

In terms of protection, the fingertip length outer coat and fitted hood, and even long "half length zip" pullover or zip-on rain pants, or loose-fit rain chaps, may be indicated.

MontBell U.L down, or synthetic, inner jackets offer warmth for almost no appreciable weight.

If you have been eating smart, add an outer shell and two or three layers I have recommended will very substantially help nearly any situation, except the most extreme.

I have a poncho tarp, a MontBell jacket liner, and rain chaps. These pack well, and are lightweight.

I accept some people just do not feel protected in wind and rain unless they have a rainsuit jacket and pants. In that case, I do recommend the not strong and durable but lightweight and breathable ProVent, O2 Rainwear, Frogg Toggs, or DriDucks rainwear.

If the temperature plummets, and it has become really cold, I recommend a bivouac. It is difficult, if not impossible, to cover ground in "whiteout" of snow or a really wet fog or clouds. Use all your extra clothing. Maybe hold back one pair dry socks. Use that shelter we discussed at 10 Essentials shelter, or a snow cave.

This is as good a time as any to discuss hats. The right hat can make a difference. If you are cold, put on your hat. If you have on your hat and maybe gloves, and you are all bundled up, and you are still cold, put on put on a facemask to preheat all the cold air you inhale.

I like the PSolar.EX facemask or the PolarWrap Warm Air Mask, Full Head Cover or ExChanger II, because these specially prevent having to heat cold air at every in breath.

Hats should be windproof or ventilate, protect from the sun, and have a front visor that could keep rain off your eyes. There are hats that have a removable wrap to protect your neck from the sun worth considering.

The effect is feeling warmer.

If excessively hot, I wear and use the Original Kool Tie, soaked in water a minute or two for slow evaporative cooling. I also have a "HyperKewl Evaporative Cooling insert for Baseball Cap" inside my hat. It works on the same principle: soak, and enjoy slow evaporative cooling. It is helpful to wear a mesh hat or vented hat with this product.

For mosquitos, black flys, no-see-ums and midges, I have a Bug-Me-Not Head Net worn over my hat. The same company also has hats, having built-in head net bug protection and elastic that secures the bottom of the head net under your arms. This keeps the biting bugs out.

Please do not use Permathrin impregnated clothing or spray-on product: Permathrin kills bees. We need bees to pollinate crops for our food.

Gloves are important extra clothing: warm, windproof, water resistent, or waterproof, not too tight to restrict circulation and allowing good dexterity, fit is important.

Extra socks can make, or break, an emergency situation. Feet crippled by blisters are not fun. People have ignored their feet, but this is not advised. Wet socks make blisters faster, where dry socks can warm a person all over. I put my dry socks in a plastic bag. This way, dry socks are available.

May I ask? Are you wearing practical adventure travel shoes or boots? If not, not much here will help. Take care of your feet.

Try on new hiking boots or shoes wearing the socks you will wear, shove your foot back, lace up, then stand up on a steep slope and bounce. Do you toes hit in front ? In addition, the volume of your foot is important. Is your foot thin? or thick? The widest part of the shoe or boot should be located at the widest part of your foot. If the heel isn't sufficiently narrow, or wide, and the forefoot of the boots or shoes are not sufficiently narrow or wide, or if the stitching hits your foot or toes, forget it. Try another brand.

Salomon brand fits me. What fits you?

Have sunglasses. The special UVA and UVB sunglasses, with Croakies sports eyeglass holders, for example, are recommended.

The lens color for mountains is different that ordinary sunglasses, however, and non UVA and UVB dark sunglasses will only open the pupils of you eyes up to be more easily injured by the intense high altitude light. Do not wear non UVA and UVB sunglasses.

I have overglasses sunglasses for sailing and for kayaking, covering side entry of extraneous light, as well.

If glacier travel is planned, special color glass and specially made "glacier sunglasses" are a requirement for the extra UV of glacier travel. The sides and edges are closed to light, as well.

Special crevasse rescue technique and equipment is a necessity: if you have no proper mittens or gloves and no jumars on "foot loops", you don't know how to use jumars, or equivalent, you are not properly roped up, you don't know self arrest having and using an ice axe, and you can put something across under the rope so the rope does not cut in to the snow or ice at the top of the crevasse, and so, your rescue can not bring the person all the way out, should the snow give way or someone falls into a crevasse, you are an accident death waiting to happen.

It is extra cold in there, so cold you must act decisively and immediately to get out before you lose dexterity of your hands, become uncoordinated, and core temperature drops precipitously right down to death. On a crevasse, use the ice axe shaft end as a probe, for each step. If the hole made is curiously light, not dark, cautiously get away.

I have been led over a snowed over crevasse. I set my feet and jerked that jerk's rope, and he came down the snowy slope head first. His ice axe holes also showed light blue light. This is no joke. I didn't hurt him. That would be stupid, putting me at risk as well. He had moved far ahead. It was nice soft snow.

However, glacier travel is for mountaineers. I am a mountaineering rope leader.
I do Mountain Rescue.

An experienced mountaineer lectured about a failed rescue: the climber had fallen into a crevasse. He was brought up almost out of the crevasse, however the rope cut into the top snow and he died only a few feet from the top: no one could get him all the way out of the crevasse.

That unhappy experience happened over 40 years ago. Now, experienced rescuers know to place an ice axe or pack or equivalent under the rope, at the edge.

Is everyone with you that knowledgeable?

There is adventure travel, and there is adventure stupid. Now, there is adventure smart.

Hiking and backpacking on trails is perhaps a more intelligent choice.