When the mercury plummets and the land turns white, nothing keeps you warm like a coat of down.
The North Face Summit Jacket
It really doesn’t matter when the mercury dives. Whether you’re under the full glare of a midwinter sun or shivering through a Fourth of July night high in the Rockies, one thing is on your mind: staying warm. Trouble is, your insulation must fit into a crowded pack. So how do you maximize warmth while minimizing the weight on your back? Enter the goose, whose feathers are more precious than gold in cold conditions.
Generations of savvy backcountry adventurers have relied on down jackets because they insulate superbly with little bulk and weight. High-quality goose down is so light and fluffy that a single ounce fills 600 or more cubic inches (about three gallon-size milk jugs) under laboratory conditions. Add a nylon shell, a few zippers, and several yards of stitching, and you have a jacket that insulates with incredible efficiency, but still compresses to half the size of a football.