treating hypothermia, heat stroke, dehydration and hypoxia, as these are rarely encountered in daily life. Leave No Trace is the backpacker's version of the golden rule: To have beautiful and pristine places to enjoy, help make them. At a minimum, don't make them worse. Distress signaling is a skill of last resort. Related activities Winter backpacking Winter backpacking requires a higher level of skill and generally more specialized gear than in other seasons. Skis or snowshoes may be required to traverse deep snow, or crampons and an ice axe where needed. Winter sleeping bags and tents are essential, as are waterproof, water-repellent, and moisture dissipating materials. Cotton clothing retains moisture and chills the body, both particularly dangerous in cold weather. Winter backpackers stick to wool or synthetic fabric like nylon or polypropylene, which hold less moisture and often have specialized wicking properties to dissipate sweat generated during aerobic activities. Layering is essential, as wet clothes quickly sap body heat and can lead to frostbite or hypothermia. A winter bivouac can also be made in a snow cave. It has thermal properties similar to an igloo and is effective both at providing protection from wind and low temperatures. A properly made snow cave can be 0 °C (32 °F) or warmer inside, even when outside temperatures are −40 °C (−40 °F). It is constructed by excavating snow so that its entrance tunnel is below the main space in order to retain warm air. Construction is simplified by building on a steep slope and digging slightly upwards and horizontally into the snow. The roof is domed to prevent dripping on the occupants. Adequate snow depth, free of rocks and ice, is needed — generally is sufficient. A quinzhee is similar, but constructed by tunneling into mounded snow rather than by digging into a natural snow formation. Fastpacking Fastpacking is a recreational activity that combines lightweight backpacking with running, and, on steep slopes, hiking. It is a multi-day adventure that usually takes places along long distance trails. A sleeping bag is carried and other essential backpacking items, and often a tent or similar shelter, if places to stay are not available. Other Canoe and kayak camping Bicycle touring and its lightweight variant bikepacking Trail riding, where gear is carried in saddlebags Backpacking (travel), where public transport is used to visit cultural attractions, rather than natural ones, though it may also include wilderness side