GRUNGY AND SNUG are what you'll get and how you'll want to stay when you go cold-weather camping. Grungy is built into messing about in the great outdoors, and reminds us, as we were born knowing, that getting really scuzzy is grand, when you know there's a hot shower and a warm bed at the end of the trail.

Snug is what you want to concentrate on, because if you can't stay reasonably warm, you can't enjoy the winter world. Most campers won't even try it, which means that you're likely to have the Blue Ridge or the beach pretty much to yourself, if you don't count the deer and the ducks and all.

But is it worth the trouble? Why not just stay home and watch David Attenborough reruns until Easter?

Well, in the first place, it doesn't often get all that cold around here, and when it does, it usually doesn't last very long. Five or ten degrees below freezing is about as low as our mercury generally drops; that feels cold when you're commuting between an overheated office and an overheated home, but it's no big deal if you're dressed for it.

And on a cold day you can see forever. The clear, crisp air seems to magnify views, and muted colors seldom noticed in summer are highlighted by contrast with a background of black and tan and brown. With its covering of foliage mostly gone, the shape of the land is seen.

In a winter-still wood the buzzing of a chickadee can seem raucous, and you hear the wingbeats of the jay that's swooping in behind, just before its shriek starts you out of your boots. Did you know a nuthatch whispers and chirrs to itself almost continually as it prospects the crevices in the treebark? That a chipmunk will sometimes climb up on a sunny stump and let out howls suggestive of some huge and demented tropical bird? That deer will sometimes follow you through the woods?

The birds and animals that don't hibernate or migrate have to work harder for their living in cold weather, and their increased activity among the leafless trees and on the barren ground increases the chances of seeing them something like tenfold. There are beavers nearly everywhere in this region, and not a few otters; coyotes are becoming common, which would be better known except that, perhaps because of the extensive interbreeding that leads them to be called coydogs, they bark and howl much more circumspectly than their western cousins.

The cries of the night creatures, unmuffled by vegetation, echo for astounding distances in the winter night. A bobcat's primordial screech may carry for a mile or more, and its effects on your psyche may be such that, for a moment, your tent becomes a cave, and your soul knows where gods and devils came from. In the higher and more remote elevations of the Appalachians, if you're very, very lucky, you may hear what you imagine is the coughing, snarling scream of a mountain lion, and it may not be just your imagination: Now that the eastern mountains are once more thick with deer, the puma seems to be making a modest comeback.

In winter the watcher in the woods who can sit still for an hour or more has a considerable advantage, because the wild things must be up and doing or starve. Be still -- really still -- for that long, and the creatures that are not downwind will forget the clumsy beast who came crashing and stinking into their neighborhood, and will go on about their business right in front of your eyes.

But to be able to be still you must be warm, and the secret of that is having the right clothing and equipment, of course. The hard part -- besides getting up the scratch to pay for the stuff -- is getting good advice about what to buy. Many store clerks don't really know much about what they sell, beyond what it says on the tags. This is as true at Sears, the world's largest retailer, as it is at K mart.

Sadly, it is increasingly true at the outdoor specialty stores, such as Eddie Bauer, Hudson Trail and Appalachian Outfitters, which used to be entirely staffed by outdoorspeople who were not just knowledgeable but zealots about the equipment they sold. They're nice people, all these people, but if you follow their advice without testing it, you may find yourself up the creek with a broken paddle. If the clerk you're dealing with sez he or she dunno, or you suspect it, ask (demand, if you have to) to speak with somebody who does know.

The key question to ask is: "Have you tried this yourself?"

Take the new polypropylene longjohns, for instance, which are the hottest thing (sorry) in outdoor wear this season. All the clerks swear by them, as well they might, at $25 to $60 the pair. Polypro's the way to go, they chorus, because it wicks body moisture (used to be called sweat) away from the skin, so you stay dry and warm.

I got this spiel from clerks at every major outfitter in this area, and it's halfway right. The stuff keeps you pretty dry but, when worn in place of regular thermals, it feels clammy, especially during rest breaks. If you're the sort of person who likes to sit long and quietly watching for wildlife, polypro thermals will leave you feeling naked.

But that doesn't mean polypro is bad news. It's great stuff, used right, and you probably shouldn't go out without it. Polypro as the single thermal layer is wonderful for runners and for the sort of hiker who goes steaming steadily along, taking pleasure from the cardiovascularity of it all, rather than from savoring the landscape. It will keep that sweat moving away from your skin, but the evaporation will also take away body heat. That's fine as long as the physical activity is fairly continuous, but when you stop you'd better go inside or have something really warm to put on.

Polypro's also wonderful for the poke-along wildlife watcher, when worn under regular longjohns or, perhaps even better, under a set of the quilted thermal underwear that goes for about $15 at Best or Wards. Polypro is also made in layered versions, with other artificial fibers or wool, all of which feel better on the skin than the straight stuff, and seem to be somewhat warmer. But don't make the mistake of subsituting polypro, blend or no, for your regular longjohns. I made that mistake recently, and spent a miserable day of twitching and shivering. Polypro doesn't replace anything, it just helps the rest of your clothing keep you warmer.

Another thing that the salespeople will try to sell you is insulated boots. While it is not entirely true that there is no such thing as a really warm hiking boot, it's so nearly true as to make no nevermind. The exceptions are huge clumsy things you can barely walk in; most have heavy felt inserts that are only modestly efficient insulators and tend to disintegrate fairly quickly. For a day of sitting in a duckblind, they're fine; on the trail they can be torture.

What you want is a Rocky Boot or the equivalent: a sturdy but very lightweight boot designed for warm-weather hiking. And you want it two or three sizes too big, because the warmth is going to come from the humongous thick wool socks you're going to wear, and the way you get those is, you buy a pair of thick wool-blend socks about two or three sizes too big, and you wash them in hot water and toss them in a hot dryer, and they shrink down to your size, only now they're twice as thick. Pull them on over thin cotton or polypro socks, slip on your light boots and, hot dog, your feet are cozy, cushy warm, and they're going to stay that way, all day in your boots and all night in your bag. The socks have so much absorptive capacity they won't even start to stink for about three days.

Another good thing about this method is that the boots need little or no breaking in. I bought my Rockies in New Mexico this fall after an airline ate my hunting boots, and wore them right out into the canyon country with never a blister, twinge, slip, twist or stumble. I love them with a passion that borders on the indecent.

That sort of attitude is common among "serious" hikers and campers, particularly the hard-core backpackers, because when you're waytohellandgone out there, you're nearly as dependent upon your equipment as is a mountain climber. You will love a sleeping bag that keeps you snug in a camp swept by a freak cold front; you will hate a raincoat that soaks through; you will cherish a tent that holds up through a howling storm; you will despise a cookstove that won't light in the rain, or that coughs and sputters in the cold.

We're not just talking things here, we're talking serious relationships.

Cold-weather camping divides sharply into backpacking and any other kind. Equipment's not all that critical when you can heave everything and the kitchen sink into the car and drive to a campsite. But when you pack it in, you'd better pack it very thoughtfully. If the car-camper forgets the matches, it means maybe a long drive to the general store; if a backpacker can't build a fire, it may mean irreversible hypothermia.

That's one of the reasons backpackers should never go alone; two people are less than half as likely as one to forget the same critical item. Another reason is that if your stove quits, your partner's probably won't. And, when hypothermia is coming on, the victim is usually the last to notice.

Make a list, check it twice. Set up a mock camp in the living room, to see that everything's there, and functioning. Put on your hiking clothes, load up the pack and take a long hike around the neighborhood, to see if the rig can handle the load and you can handle them both. After you've built a good sweat, take a good long break, to see if you can sit still without getting too chilled.

If you're a newcomer to backpacking, it's a ood idea before buying your outfit to read a couple of the paperbacks on the subject that are to be found wherever camping equipment is sold. Seek advice from friends and co-workers. Be prepared to spend money, because all the good equipment, and much of the rest, costs too much.

But the single, central principle of selecting outdoor gear is:

If it isn't too big, it's too little.

That is to say:

* Clothing. If you normally wear a Medium, get a Large or even an Extra Large, because you're going to be wearing lots of layers, and if your clothing binds, it loses most of its warmth and nearly all of its charm. If the coat or vest you're looking at is foreign-made (and most of them are, anymore), be careful, because what they regard as Really Big in Taiwan may translate into no more than Medium in American.

* Sleeping bags. Nothing has yet been invented that's as light and warm as a great big top-quality down sleeping bag, but you can't afford it, and anyway you're in trouble if down gets wet because then it loses all its warmth, so forget it. Buy the biggest, cheapest down bag you can find and slip it over another, good-quality sleeping bag insulated with an artificial fiber such as Holofill II, which will keep you fairly warm even when it's mighty wet. This double-bagging gets you the best of both worlds, and both bags will go into a normal-size stuffbag if you stuff hard enough. While it means you'll be packing a couple of extra pounds, you'll be snug and smug as you lie there listening to your tentmate whimper with the cold.

Remember, get big bags, because you'll want to keep your outer clothing and a water bottle and other stuff in there with you; a bag that seems big enough for two in the store won't be a bit too big for one in the woods. While you're at it, get the longest and widest of the closed-cell foam sleeping pads.

* Tents. A so-called one-man tent is barely adequate for a medium-sized dog, and a two-man tent will give you less than enough room to swing a cat. A four-man tent, which will weigh at most a couple of pounds more, will decently accommodate two people, or possibly two adults and a well-behaved child. Also, it will allow you to get your gear under cover and still leave room to eat inside, which in a cold rain can make the difference between moderate inconvenience and utter misery.

An external-frame model is often more convenient, but the pole-and-guyline models generally offer more headroom, which grows more important the longer you spend inside. But throw away those crummy metal tent pegs and buy the big plastic ones, which are virtually indestructible.

* Finally. While thinking big is critical in terms of clothes and equipment, think small when planning trips. In winter, figure on taking twice as long to go half as far, and pitch camp in midafternoon, because it will be dark before you know it. You may be ready to hit the sack by six o'clock, and to stay there till the clock says six again.