A bivouac in winter at Benediktenwand, Germany.

A bivouac sack, bivy, bivy sack, bivi bag or sometimes, in the UK, Emergency Sack or Survival bag, is an extremely lightweight, waterproof alternative to traditional tent systems. The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom, the UK or Britain,is a Sovereign state located A survival bag is a person-sized waterproof bag typically orange in colour designed for use in Wilderness, Mountain, Forest Upland or A tent is a shelter consisting of sheets of fabric or other material draped over or attached to a frame of poles or attached to a supporting rope It is used by climbers, mountaineers, hikers and minimalist campers. UserStan Shebs for a timetable --> Climbing is the activity of using one's hands and feet (or “Alpinist” redirects here See also Alpinist (magazine Mountaineering is the Sport, Hobby or Profession of The word 'hiking' is understood in all English-speaking countries but there are differences in usage A bivy sack at its barest is a thin waterproof fabric shell designed to slip over a sleeping bag, providing an additional 5 to 10 °F of insulation and forming an effective barrier against wind chill and rain. A sleeping bag is a protective "bag" for a person to Sleep in essentially a Blanket that can be closed with a zipper or similar means and functions as Fahrenheit is a temperature scale named after Daniel Gabriel Fahrenheit (1686–1736 a German Physicist who proposed it in 1724 This page is for the movie "Wind Chill" For the term see Wind chill. Rain is Liquid precipitation. On Earth it is the condensation of atmospheric Water vapor into drops heavy enough to fall often making it to A drawback of a simple bivy sack is the humidity that condenses at the inner side leaving the occupant or the sleeping bag moist. Condensation is the change of the physical state of aggregation (or simply state of matter from gaseous phase into liquid phase Better bivy sacks consist of Gore-Tex (or a similar breathable fabric) to allow the humidity to pass. Waterproof fabrics are usually natural or synthetic fabrics that are laminated to or coated in some sort of permanently Waterproofing material such as Rubber,

Very similar is the swag, very popular in Australia. Swag2jpg|thumb|300px|Rolled swags]] In Australian historical terms a swag is a portable shelter that is rolled (usually with belongings inside and carried on a person's For a topic outline on this subject see List of basic Australia topics.

Rock climbing bivouac in Yosemite National Park

Nowadays there also exists the bivouac shelter or "bivy shelter", a compromise between bivy sack and single-person tent. Rock climbing is a Sport in which participants climb up or across natural rock formations or man-made rock walls with the goal of reaching the A bivouac (pronounced /ˈbɪvuˌæk/ biv-oo-ak traditionally refers to a military encampment made with Tents or improvised shelters usually without shelter or protection from A tent is a shelter consisting of sheets of fabric or other material draped over or attached to a frame of poles or attached to a supporting rope Using hoops or poles, a bivy shelter is usually supported along its length just enough to keep the fabric off of the occupant, and especially to provide some additional breathing room around the head.

In contrast to a bivy shelter, a traditional bivy sack typically cinches all the way down to the user's face, leaving only a small hole to breathe or look through. Many campers gladly accept the increased carrying weight of a bivy shelter for the huge increase in comfort it affords. However, the traditional bivy sack certainly still holds its place among mountain climbers and backpackers, and is frequently carried on long or dangerous hiking or hill walking expeditions and high mountain climbs as a compact emergency shelter. Backpacking (in US tramping, trekking, or bushwalking in other countries combines Hiking and camping in a single The word 'hiking' is understood in all English-speaking countries but there are differences in usage In Britain, the term hillwalking or fellwalking is normally used to describe the recreational practice of walking in hilly or Mountainous terrain generally A mountain is a Landform that extends above the surrounding Terrain in a limited area with a peak

In the UK, Bivy shelters have become very popular amongst coarse fishing and large Carp fisherman, who, in pursuit of their quarry, fish throughout the night. Coarse fishing is an angling method mostly popular throughout the United Kingdom and mainland Europe. Carp is a common name for various Freshwater Fish of the family Cyprinidae, a very large This upsurge in popularity has increased competition amongst manufacturers and designs have become more advanced.

An alternative spelling is "bivvy".