Ascending steep slopes
Sometimes ascending is nearly impossible, e.g. in steep, deep, wet or icy snow. It helps to have some aids on hand for these times, particularly when on a multi day tour. With the advent and refinement of pattern base skis, grip waxes are not used much outside racing circles, but every so often there will be a time when your skis just will not grip on the way up a slope. If your technique, pattern base and fitness are not enough to get you up that hill, you can reach into your bag of tricks and put on some skins, ski ropes or a grip wax.
Originally skins were a strip of mohair or sealskin strapped or glued to the ski base to provide excellent traction for climbing hills, while still allowing some slip for a downhill run. Nowadays skins are synthetic but are still glued or strapped to the base of skis. They are simple to use and easy to store. Old skins seem to stick better if they are dry, and applied to dry skis, which is often not easy to achieve in practice!
Ski ropes are a cheap alternative to skins. Using about 4 m of approximately 4–6 mm diameter rope, tie a small loop in the middle, place this over the ski tip and lace the rope under and over the ski from tip to tail. They take a while to put on but cost virtually nothing and are excellent for a difficult ascent.
Grip wax (klister)
Most skiers will not go near klister wax because it is so messy. However, it is the most versatile and useful grip wax that a ski tourer can use in an emergency. Klister is a tacky fluid (unlike most ski waxes which are solid) and will stick to most old snow when the crystals are rounded and wet. Klister comes in squeeze tubes and small cylinders, and is easiest to apply when warm. The best warming spot is usually the armpit or in the hands. Apply it in short diagonal stripes on the base of the skis, then spread out and work it into the ski base with the palm of your hand. It is messy, but because the palm of the hand will be warm (at least by the end) the klister will spread evenly. It greatly improves traction, but does not reduce downhill running speed as much as skins or ski ropes.