A lot of hikers and backpackers pretty much stop hiking and backpacking in winter. For the ones the keep it up, there are quite a few rewards to be found.
For one thing, trails that are so popular that they’re nearly highways in summer often become nearly empty in winter. The result is that the solitude and serenity that many hikers crave is easier to find.
For another, the snow transforms the mountains. The blanket of fresh snow softens jagged peaks, adds contrast and color against the black basalt and serpentine, and in some cases the snow is even deep enough to change the shape of entire mountains.
Of course, hiking in deep snow is tough, so it’s advisable to use snowshoes or cross-country skis to cover some distance. There are some folks who wear snowshoes to climb big hills, and carry skis so that they can swap for the descent.
It’s even more important to be prepared for winter trips than for summer trips. First, be sure to bring layers of clothing, and especially avoid cotton. Even more than in summer, cotton can kill by staying wet and thus inducing hypothermia. Get a wicking base layer, and lightweight wool or fleece midlayers, plus a windproof shell. Get used to removing layers during periods of high exertion to minimize sweating, and putting them back on during breaks in order to stay warm. And keep a good, warm, hat handy — it needn’t be expensive, even a Gore Windstopper fleece hat can be had for $30 or thereabouts at places like REI and Outdoor Research. A good pair of gloves, with waterproof mitten shells, can help keep hands warm on cold days. Some people like to wear gaiters, but this is a personal preference. They can help to keep your feet and legs a little bit warmer, and also keep snow out of your boots. Finally, be sure to wear warm socks — layers help here, also. I generally wear a wicking liner sock under a heavier wool sock for warmth.
Footwear for snowshoeing is also important — waterproof hiking boots are generally the most comfortable, and boots with one-piece uppers are generally sturdier than multi-piece uppers, which helps to prevent the straps on your snowshoes from pinching your toes and restricting circulation.
Trekking poles with winter baskets can be helpful, for probing the snow to find hidden holes, as well as for balance.
The Mountaineers Press has an excellent book describing popular snowshoe routes: http://www.amazon.com/Snowshoe-Routes-Washington-Dan-Nelson/dp/089886884X/ref=sr_1_1?ie=UTF8&qid=1291405023&sr=8-1
And last but certainly not least, always check the Northwest Weather and Avalanche Center (http://www.nwac.us/) before heading out. The best way to avoid avalanches is to heed the NWAC warnings, and avoid areas listed as high having avalanche hazards.
Get your winter gear ready, find your route, check the NWAC report, and have some great trips. Don’t forget your camera!