Bivy bag
שק ביווי A bivy bag is a sack worn over the sleeping bag or clothing. It's usefull for climbers who attempt a long route but fear getting stuck at night and having to bivy. They do not want to carry complete bivy gear (sleeping bag etc.) because then they might not be fast rnough and may definitely have to bivy...
Some climbers like to always have a bivy bag, for such cases, and feel a bivy bag is essential gear, just like a head lamp.
Some bivy bags are made of NyLon and others from breathing materials, such and Goretex. NyLon is cheaper but does not allow moisture to pass freely. Water apor from breathing can then condese on the bag, that's cold because of the night air and you might awake wet. Breathable materials do a better job keeping you warm and dry, but are more expensive.
In recent years it's easy to find elaborately made bivy bags, with a short tent pole over the sleeper's face, to allow better circulation. Mark Twight says it's just exess weight, and i tenfd to agree...
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Contributions to this page were made by Mica Yaniv and others...
