It has been called the ultimate ski experience . . . the essence of freedom and weightlessness for the alpine addict no longer content to buck 45-minute lift lines and chopped snow.

IT, of course, is helicopter skiing. This is the year heli-skiing seems to be really arriving. And with good reason.

"The great mass of skiers today have been skiing six or seven seasons. These people are good now and they're looking for something new," explained one helicopter ski representative.

After viewing the crowd of people inundating the Mountain Canada table following a heli film in the Banff Springs Hotel here one recent Sunday, I would agree. As the ski season winds up for the year in many places further south, Canada's heli companies are now in high gear. Peak season is late February through early April.

Helicopter skiing started in Canada's western mountains during the mid-1960s, and for a long time it was the exclusive property of the talented few. People who helicopter skied then were made of the same stuff as those strange souls who climbed mountains with metal spikes. They usually had been skiing from the time they could walk and looked better on the mountain than the pros.

Heli films didn't hurt that image, packed as they were with crazies like the California surfer who came down one mountain at 60 mph on a surfboard.

But slowly, things are changing. The heli-skiers these days are slightly different and so is the sport.

In early years, one climbed into a small chopper by day and slept in rough trailers at night, seldom with the luxury of a private room and certainly without private bath. Yes, the rough edges do remain. But a lot of them are being smoothed out.

Canadian Mountain Holidays, by far the largest heli-ski operation in the world, serves seven areas while hauling upwards of 4,000 people a season to virgin peaks across the Canadian West. Last Christmas the company opened a $3-million heli-ski lodge, complete with private rooms and baths, in the Bobbie Burns range.

A couple of CMH operations now use hotels in backwoods logging towns, peopled with crusty loggers and even crustier bars.Not exactly the Hilton, but more luxurious than bunk beds in a trailer. And one of CMH's most popular spots is located in the middle of an actual ski village called Panorama. Unlike the usual heli-ski center, Panorama is set up for standard skiing (chair lifts, T-bars, etc.) and the helicopter operation is only a sideline.

The newest wrinkle allows two things originally unknown to helicopter skiers: lodging in condominiums with all the usual amenities, such as good restaurants and (praise be) hot tubs, plus a special introductory heli program for Eastern skiers who want a taste of the real thing without having to plunk down $175.

All of which brings us to the main point of how helicopter skiing today is accommodating itself to that great mass of intermediate skiers.

It helps to understand what helicopter skiing is all about.

There are two ways to helicopter ski: the five or seven-day package or daily skiing. The week-long package is expensive but nice. You're with the same eight or nine people day and night. The skiing is intensive, the scenery outrageous, and you form the kind of fast, deep friendships that come about under special situations. There are usually several groups staying at the lodge during that week, so after the first few runs the whole lot of you are separated into skill groups. The powder experts disappear over the horizon for the steep and deep. The first-timers stick to tamer (but no less lovely) terrain and set a more relaxed pace.

Daily skiers often don't have the luxury of being segregated into skill groups, which can make it tough on the poor soul who falls 20 times the first hour while half the group impatiently grits its teeth. But a one-day shot is far less imposing (financially and psychologically) than a week's commitment.

Day and week heli-skiers, alike, are outfitted with Skadi avalanche beepers, drilled in their use and warned to ski only where the guide tells them. The guides carry a pack crammed with safety and repair equipment.

Whether it's by day or week, your helicopter is usually carrying several loads of people. As soon as you're dumped atop your own private peak, it disappears for the second load and a third (and sometimes a fourth), then returns at a designated pickup spot below for your second run, and then goes off for everybody else's second runs, etc.

Yes, it gets hectic. But not so hectic that you don't have time to stop and gawk at those magnificant peaks. Western Canada's mountains are among the loveliest, rolling in platinum waves as far as the eye can see . . . huge, tortured plates shoved one atop the other, their folded lines delineated in snowy dust, thrust sharply toward the sky.

There is a feeling of power being up there, virtually alone against the elements. And a sense of soul-deep satisfaction when you look back after that first really good run. Those skinny, swerving lines are yours, an ecologically safe scrawl of your own personal graffiti across the face of nature.

Enough people have yearned for this experience that most heli companies now fly nine or 12 passenger jet-powered choppers instead of the two- or three-people jobs used in early years. Last year, CMH alone took approximately 4,200 people helicopter skiing. Of this group, 52 percent were from the United States, 31 percent from Europe and, surprisingly, only 16 percent from Canada. The heli idea has caught on so well that CMH now offers heli-hiking during the summer and Mountain Canada does heli-cross-country skiing.

But with increased popularity have come increased problems. As one powder instructor bluntly put it, "heli-ski companies were starting to get a lot of people with more money than ability. It was hanging up day groups."

Enter two badly needed innovations: the screening course and the intro course.

You don't have to sign up for Banff Club Ski's one-day "Powder, Bumps and Bushes" class, but if you're a powder novice from the East it's a good idea. The instructor spends six grueling hours leading you down the back bowls and tree slopes of the Lake Louise and Sunshine ski areas near Banff. He shows you how to ski powder and trees and gives you an honest assessment of your talents (or lack thereof).

One Australian, convinced that he had been sold a bill of goods by his travel agent back home, staggered out of the PB&B class to the heli-ski company where he was signed for a week package and begged out. They listened to his story and let him cancel (with refund).

The second way to taste heli-skiing is the introductory program at Panorama, 100 miles from Banff. For $85 (as opposed to $175 regular daily fee) you spend the morning skiing Panorama's regular slopes with a powder instructor, then catch the 11 a.m. chopper to a nearby peak, eat a box lunch among the clouds and ski virgin snow back to town.

For those of you who may be seriously considering this latest in ultimate ski chic, here are answers to many of your remaining questions:

Skiing Ability

Paul Neale of Mountain Canada says if you're a strong intermediate skier, with emphasis on the word STRONG, you can probably handle it. You need control so you can obey guides when they tell you where to ski. You need aggressiveness to cover those conditions (like crusty snow, steep chutes and trees) where you might be scared silly. And you need to be in decent condition. Yes, powder skiing is more finesse and style than brute strength, but digging yourself out of hip-deep powder after your 15th fall of the hour is hard work. A writer for Ski magazine warned, "getting up out of a divot in three feet of snow is the energy equivalent of 100 pushups."

Preparation

Exercise like mad, work on leg strength and endurance and try to have a week or so of skiing under your belt before you climb into a helicopter.

Weather

January and February are usually cold and stormy but that also makes for a lot of deep powder. Later months have warmer weather, fewer storms and less likelihood that you'll spend the day skiing trees in a blizzard.

Danger

Yes, it exists. Canadian Mountain Holidays has had 10 avalanche deaths in 18 years along with four lost in a helicopter crash and two who died in tree accidents. All skiers carry radio beepers and do avalanche drills before taking off. Guides are trained to treat broken bones on the spot.

Prices

All rates are in Canadian dollars, worth 20 percent less than U.S. dollars. Intro course is $85, one-day trips are $135 during low season (December and January), up to $175 during high season (February to April). Five and seven-day packages run along a sliding scale from about $1,100 to $2,300, with peak prices coming in March.

Heli-ski companies measure their product in guaranteed vertical feet, with daily operations promising you about 10,000 feet, weekly operations promising 100,000 vertical feet. If you fly more, you pay extra. If you fly less (because of bad weather or equipment breakdowns) you get a partial refund.

Heli Ski Areas

A story in Ski Magazine this season listed heli-ski companies in Alaska, the United States West (including Utah, California, Wyoming, Nevada, Idaho, Colorado) and Canada. Canada is where it all began, and among the top companies operating in the Canadian West are:

Canadian Mountain Holidays, Box 1660, Banff, Alberta, TOL-OCO. Telephone (403) 762-4171.

Mountain Canada, Box 1530, Golden, B.V., VOA-1HO. Telephone (604) 344-5410.

Mike Wiegele Helicopter Skiing, Box 1824, Banff, Alberta, TOL-OCO. Telephone (403) 762-4171.

Selkirk-Tangiers Helicopter Skiing, Box 1409, Golden, B.C. VOA-1HO.

BC Powder Guides, Box 258, Whistler, B.C. VON-1BO.