Letter Re: Bivouac Bags

Hi.
As I read “Prepare or Die” I thought of one other item that could be very useful which is a Bivouac (“Bivy”) sack. I recently purchased one of these from Campmor for my Bug Out Bag (BOB). It takes the place of a tent. It is basically a waterproof, breathable sack which will entirely enshroud your sleeping bag. Mine was only about 1 pound and under $100. It takes up very little space when packed and according to the REI web site a bivy sack can add 10 degrees more warmth to the rating of your sleeping bag- an important thing in cold climates! These sacks also often come with a mosquito net for summer use. Thank you for your site. I have learned much since I found it last year. – Karen on Massachusetts

JWR Replies: In my experience, bivy bags gradually build up too much internal moisture when used on extended backpacking trips in cold weather. But they are fine for weekend outings. In foul wether there is no substitute for a four season tent with a rain fly–where you can keep your gear dry and have room for changing clothes. .