We've seen climbers and hikers carry too little protection from the elements (and suffer)... or carry full bivi gear, when they could just carry or wear a lightweight cagoule. 

One of our cagoules -- at ~1 lb. 4 oz. (.6 kg) -- might be the right answer, even for a bivouac.

What's a bivouac, and what does it have to do with a Northwerks^TM  full-length cagoule?

A bivouac is camping in the open, unsheltered by a structure or tent. There are times when climbers and hikers get caught out by an afternoon downpour, or by night falling before they reach shelter. We have passed tolerably comfortable nights during the summer season climbs in the Alps and Tetons bivouacking in our cagoules. A few tips for overnight bivouacs:

• Under your cagoule, put on as much warm clothing as you can. A warm hat will make a big difference.
• Use your climbing rope as a sleeping pad... uncoil it and lay it down a strand at a time in close parallel, so that you have 10 mm of nylon between you and the cold, hard ground. One rope will cushion two or more people.
• Use your boots as a pillow. Seriously.
• Put your feet in your rucksack, and pull the cagoule down to full length, over the top of the rucksack. If you have an extension sleeve on the rucksack, pull it up around your waist for extra warmth.
• While use of an umbrella during a bivouac is considered dashing good form, it is really not necessary. 

Above: On the Dent du Geant (Giant's Tooth), 4013 meters, French Alps. We bivouacked in our cagoules that night, following the method outlined in the text above.