In cold weather camping, one of the best things you can do to stay healthy is develop a drinking habit. I'm talking water, not wine.
Adequate hydration is key to avoiding hypothermia and altitude sickness.
In freezing cold weather, look for flowing water. A lake may be frozen solid, while a stream or even a tiny spring might be flowing well. Shovel snow into the garbage bags and set them in the sun. In a couple of hours, you'll either have some melt water, which can be funneled into a pot, or you'll have almost-melted snow that will melt very quickly when it is heated. Water, water, everywhere For faster results, melt snow over either a fire or a stove.