Water management

The best way to keep your hydration system (ie. your Camel Back) from freezing on those cold early morning ascents, is to leave it behind. I know, you want to take it because it helps you stay hydrated. But the truth is, if it's freezing and windy, your tube is going to clog up with ice. Over the years, I've wrapped enough insulation around the tube of my platypus to insulate an aquaduct. I ended up not drinking on those early morning climbs resulting in a greater state of Dehydration. Don't get me wrong, I use my Platypus hydration system all the time and I love it, that is, when its not going to freeze.
For high altitude ascents and winter alpine routes, carry a small water bottle in the inner breast pocket of your jacket. Refill the bottle at break stops from larger water bottles in your pack.
This system has the advantage of enabling the climber to keep track of how much water they are consuming during the day. Also, before you leave camp, chug a liter of water and carry it in your belly.