February 19, 2001


What's the best way to protect your water supply when it's freezing?

Dear Gear Guru, I've heard stories of water bottles freezing, bursting, etc. at extremely low temps. Besides an inside-the-shell mesh pocket, what's the best way to protect your water supply when the thermometer plunges?

— Bill Maxwell Lithia Springs, Georgia

Freezing water bottles actually are a fairly serious problem. Cold air typically is dry air, and you lose a lot of body moisture inhaling, warming and moisturizing cold, dry air. So you can get easily dehydrated in cold weather. And if you don't have any water to drink because it's frozen, you may have a difficult time maintaining body temp.

So, as you mention, one good solution is to drop a bottle in the mesh pocket that many mountain-oriented shells have sewn into the lining. Some have two or more. Several years back, when climbing Denali, I went without pack for our summit day —- my Feathered Friends' down parka had so many interior pockets that I could have shoplifted half an REI store with it.

A second option is to get an insulated bottle jacket. Outdoor Research, for instance, makes something called a Water Bottle Parka, which is simply a foam-insulated, soft-shell jacket for a Nalgene-type bottle. The Parka comes in three sizes, from $15 to $17. I've found them to be extremely effective at keeping water liquid even for hours of sub-freezing weather. To ensure your water stays fluid for as long as possible, it's best to fill the bottle with warm or even hot water.

You also can now get hydration packs that are insulated for winter use, such as Camelbak's SnoBowl ($40). Packs such as the SnoBowl are a little plagued by freezing tubes and bite valves, but manufacturers are working on that problem. And they tend to work pretty well overall.