It's mid-February in Snowmass, Colo., and I awaken to dream conditions: billowing clouds and freezing temperatures dropping piles of fresh powder on the slopes. In record time, my husband and sons wolf down breakfast so they can get in line for the first chairlift of the day. I, meanwhile, don only a thin base layer and open the vents on my ski pants. I loosen my boot buckles, slap "skins" on the base of my lightweight skis and click into alpine touring bindings - free-heeled bindings that make skiing uphill as straightforward as cross-country skiing. Better yet, these bindings can be locked down to shred the descent.

I meet up with my guide, ski instructor and Aspen, Colorado-based mountaineer Ted Mahon, and together we strike out - or, more accurately, up. Even though I can see my breath, within minutes I'm warm. And though hordes of powder-happy skiers and snowboarders yell that we're going the wrong way, I am happy to swap the frenzy that comes with a big snowfall for the serenity and exercise of uphill skiing.

Once a fringe activity - and even banned at most North American resorts - "skinning" uphill is among the fastest-growing winter sports, according to Snowsports Industries America. I discovered it 20 years ago when I moved to Jackson Hole, Wyo., right out of college and bought a pair of Telemark skis so I could explore the backcountry of Grand Teton National Park. Back then, I had few responsibilities and entire days to devote to skiing on mountains far outside the ski resort boundary.

These days, my leisure time and risk tolerance have both decreased significantly, which makes skiing uphill on groomed resort slopes an alluring proposition. I get heart-pumping, blood-circulating cardio exercise and immersion in nature on the way up. Then I click into my bindings, add a few layers to my body and schuss down.

Here in Snowmass, I'm certainly not alone. Aspen Skiing Co. has created designated uphill trails at all four mountains that make up its resorts, stocks its rental shops with uphill equipment and offers uphill guides through its traditional ski schools.

As Ted and I settle into a rhythm, we see several groups of other uphill skiers. One is composed of healthy-looking, ageless women (seriously - they could be 30 or 60), all of whom he knows, and he tells me that many locals skin up regularly for their daily exercise. We see another pair, maybe a father and his grown son. Ted tells me he has regular clients who hire him to skin uphill with them and then give them pointers on the way down.

Does one need a lesson to ski uphill? Of course not. If you can walk or shuffle, you can ski uphill, provided you have the right equipment.

The general term for the equipment is "alpine touring" - also known as "AT" - gear. This includes the bindings that can be locked down as well as climbing skins, which are adhesive, carpetlike attachments that affix to the bottoms of the skis and deliver traction.

Aside from the exercise, uphill skiing also allows visitors to explore new areas. I follow Ted into a grove of aspens, and then our trail winds through a thick forest that has no downhill skiers. Although I can hear the buzzing of the Snowmass lifts, I cannot see them, and the experience is quite magical. It's rustic and wilderness-y but without venturing too far away from my family or creature comforts, like hot cocoa and flush toilets at the mid-station.

Not every resort welcomes uphill skiers. Many Utah destinations don't allow it, and other resorts around the country permit it only during specific hours. Some, like Eldora in Colorado and Sunday River in Maine, charge for the privilege of skiing uphill. Others encourage uphill skiing and simply ask those going up to stay out of the way of those going down.

As for who does this, it varies. I've crossed paths with Lycra-clad "ski-mo" (ski mountaineering) racers on carbon-fiber gear going light and fast. I've slogged up with fellow skiers carting big packs and going slow and steady. The common denominator, at least as far as I can tell, is that the people skiing uphill at resorts enjoy the physical effort, the beauty and the safe access, which is not guaranteed in the backcountry.

As for whether this will enhance a ski vacation for those who travel to the mountains only once or twice a winter, my best answer is yes, with caveats. Make sure you're well acclimated; high altitude makes breathing hard, and uphill skiing makes it even harder. To avoid overtaxing your body, wait a few days after you've arrived and settled in. Also make sure you bring a backpack for water and snacks (although you can always stop in a mid-mountain lodge to refuel and hydrate, so bring your wallet, too). In my pack, I also throw in a helmet, goggles, layers and warmer gloves for the descent.

Finally, remember that the journey is more important than the destination. This isn't New Age advice from a free-spirited Coloradan; it's a reminder that there can be 2,000 to 3,000 vertical feet between the base of a resort and the top. That's a long way up. If you decide to turn around halfway, that's fine.

Once you've decided you want to try it out and confirmed that your resort allows uphill skiing, the first thing to do is secure the gear. Some resorts offer uphill rentals at company-owned gear shops. If your destination does not, search for a specialty outdoor shop (ski towns are lousy with them) - chances are they offer rentals. Snowboard? They make split boards with adjustable bindings for uphill boarding.

Gear in hand, it's time to plot your path. Avoid black diamond runs (too steep and often covered in moguls). Blue squares generally offer a hearty but feasible climb. Greens are easier, but they can be long and winding, and that uphill adventure can turn into a slog.

And that's it. It's almost as easy as going on a run.

Which is why I love adding this activity to my ski vacations. It's another way to see the mountain and get a feel for the surroundings. It's also a lovely way to keep warm, a fact I'm reminded of when Ted and I reach our destination, Elk Camp, elevation 11,325 feet. We're toasty and elated, endorphins cruising through our systems. Meanwhile, frozen skiers and snowboarders disembark from the lift complaining about numb fingers and toes.

We pull extra fleeces and jackets from our packs to protect us from the wind, goggles, and helmets. Tighten our boots and lock down our bindings. It's a quick transition, and then we're flying down the slopes we just skinned up, powder billowing out from underneath our skis.

It's a full-body skiing experience, intense and fulfilling and tiring in the best possible way. It's so alluring, in fact, that at the bottom, when Ted and I say goodbye (I only booked him for the morning), I slap my skins back on, free my heel and head up for one more lap before I meet my family and ski like the rest of the world for the remainder of our vacation.

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WHERE TO STAY

-Limelight Hotel Snowmass

65 Wood Rd.

855-369-2460

limelighthotels.com/snowmass

A modern slopeside hotel that's casual-chic. Rates include a European-style breakfast buffet with fresh pastries, smoked meats, cheeses and more. Rooms from $400.

-Annabelle Inn

232 W. Main St.

877-266-2466

annabelleinn.com

This 35-room, family-owned inn in downtown Aspen is affordable and cozy, with a central fireplace and complimentary afternoon cookies and cocoa. Rooms from $175.

WHERE TO EAT

-Up 4 Pizza

Snowmass Mountain (at the top of Big Burn chairlift)

970-925-1220

aspensnowmass.com/our-mountains/snowmass/dining/up4pizza

This casual pizzeria located 11,835 feet above sea level rewards uphill skiers with a free cookie. Open 9 a.m. to 3 p.m. Nov. 28 to April 19. Slice of cheese pizza $8.15.

-Saké

110 Carriage Way

970-429-4970

sakesnowmass.com

A pan-Asian sushi restaurant that also offers traditional dishes like Mongolian beef, plus an extensive wine and sake list. Located in Snowmass Village. Plates start at $8.

-Meat & Cheese

319 E. Hopkins Ave.

970-710-7120

meatcheese.avalancheaspen.com

This rustic restaurant and gourmet food shop features locally sourced ingredients, seasonal dishes, and a shared-plate menu with a blend of Asian, European and American cuisines. Open daily 11 a.m. to 9 p.m. Boards start at $7.

WHAT TO DO

-Aspen Snowmass resort

120 Carriage Way

aspensnowmass.com

The resort consists of four mountains - Aspen, Highlands, Buttermilk and Snowmass - and each allows uphill skiing (check individual mountain websites for guidelines and hours). These mountains also offer lift-serviced skiing and riding for people of all ability levels. Hire an instructor if you're new to uphill skiing and want pointers. Open daily 8 a.m. to 3:30 p.m. No pass required for uphill skiing; pass required to ride chairlift.

INFORMATION

-colorado.com/activities/colorado-skiing