One method I've used is to tie a length of thin accessory cord around the neck of my water bottle, toss it into the stream and fish it out with a hearty yank. Actually, it's kind of entertaining trying to get the bottle as full as possible without filling it full of dirt. I always boil any water melted from snow and treat water dipped from a stream or lake. Also pay special attention to guidelines on length of water treatment vs temperature if you're using a chemical treatment system. Just because it is winter and the water is cold doesn't mean that the parasites are on vacation.
Giardiasis is a lousy way to remember that great trip.
Some folks may notice that boiled water has a rather flat taste, but I think warm snow-water tastes pretty good. Having suffered from carbon monoxide poisoning, I avoid cooking in my tent. Besides being potentially lethal, cooking or melting snow in your tent makes a lot of steam which then condenses on everything in the tent. I usually prepare most of my water in the evening, starting off by making enough for several large mugs of hot chocolate and my meal. While eating, I fill two or three Lexan bottles with boiling water, put one bottle in an insulating jacket and then stuff them all in the foot of my sleeping bag.