If you go backpacking in winter, you need to know how to select a good tent or camping spot. Three season rules do not apply!
Picking the right site will definitely increase your level of comfort, but can also protect you from serious injury. Here are some basic guidelines to keep in mind.
Avoid Avalanche Zones
Before you pitch your tent make sure that you are not in an avalanche zone. Most avalanche zones have a slope of 40 degrees or higher, so avoid camping on them or in forest area below them. If you hear cracking sounds in the snow beneath you or see evidence of a prior slide, clear the area carefully.
Do Not Camp Under Snow Covered Branches
Snow covered branches can snap at night and fall on your tent. Avoid sleeping under them to prevent injury.
Avoid Valley Floors or Deep Canyons
Cold air flows downhill and pools at the bottom of valleys or canyons. To avoid this, don't camp in a low spot.
Try to find Natural Wind Breaks
Moving air and wind will strip heat from you through a process known as convection. If possible, try to pitch your tent and dig your kitchen area behind a natural wind break such as a large boulder or small hill, or build one using snow blocks.
Camp Near Running Water
Melting snow takes a long time and burns through a lot of stove fuel. If you can find a tent site near running water, you can save yourself a lot of fuel and time by purifying existing sources. This can be done by boiling the water or warming it and treating it with chlorine dioxide tablets. Either way, you'll save a lot of fuel.
Sites that get morning sun will warm up faster in winter. They're also useful if you need to dry out your sleeping bag due to internal condensation. In such cases, you should open the sleeping bag and drape it inside out over your tent. Many cold weather bags have black or darkly colored interiors to absorb more heat and accelerate the drying process.
Flatten the Snow under your Tent
Before you pitch your tent, flatten the snow under it by walking over it wearing snowshoes or boot. This will begin a process known as sintering, where the snow will harden into a firm platform. If the tent site you have selected is not level, you can shovel snow onto it and to adjust it's pitch
Point Your Door Downhill
Point the front of your tent downhill when you pitch it. This will prevent cold air from flowing into your tent when you need to go outside.
Do you have any other advice I should add here?