Part of the fun of winter cycling is crashing through snow drifts or trying to clear a stretch of deep powder. When going through any amount of snow deeper that 6 inches, it makes a lot of sense to sit up straight, lean back, and put as much weight as possible on the rear wheel. Allow the front wheel to roll over the surface of the snow, instead of plowing through it. You’ll notice the extra speed and reduced effort right away. Steer with only with the tips of your fingers to get a real feeling for “un-weighing” the front wheel. Your rear wheel for the most part will follow in the path cleared by the front wheel. If you start to sink, push down into the pedals to more evenly distribute your weight. Without the friction of the front wheel snowplowing, you’ll have the extra bit of loft you need to get through longer and deeper stretches of snow. Just beware of the rear wheel sticking and then being pitched over the bars!
Another way to practice floating that front wheel is to practice your manuals going over snow drifts or when you’re about to cross plowed snow rutts. A “manual” is similar to a wheelie, but you stand and coast on the pedals instead of sitting and pedaling.
From pedaling speed, hover over the rear brake lever as you pull back on the handles bars. Lean back until you find that sweet spot. Conversely you may only need to clear a small object like curb, pot hole or block of frozen snow, and only need a little lift to get the wheel up and out of the way. If you lean too far, give the rear brake a light squeeze to pull the bike back under you.
If you can get that front wheel over an obstacle, the rear wheel can pretty much follow it, and that goes for summer riding too. Have fun!