It took ski instructor Bob Womack 15 years to learn how to carve a perfect ski turn. And even then he could do it only at high speed. Now he teaches first-time skiers to carve turns in two hours."At first I thought I was just a really gifted teacher," says Womack, who teaches at Sugarbush, in Vermont. "But it happened so many times last winter I knew it couldn't be just me. It must be the skis."The skis in question are relatively new. New enough that they're still known by many names: hourglass, shaped, super-sidecut, or parabolic skis. But everyone knows that those labels refer to a radical-looking shape consisting of fat tips tapering down to a sleek, narrow waist that flares out again into wide tails. Although the design seems unconventional, it's actually more evolutionary than revolutionary."Skis have had a bit of a sidecut to them ever since the late 1800s, when skiers first discovered that the ski would bend into an arc a little easier if it was a little narrower in the middle," says Joe Cutts, technical editor of Ski Tech magazine, a trade publication that covers skiwear and equipment.In 1989, Elan skis took that concept a step further by radically deepening the sidecut on one of its models. The deep sidecut, not surprisingly (for those of you who didn't sleep through 10th-grade geometry), had the immediate effect of allowing less-experienced skiers to carve sharp, tight turns. To illustrate the concept, imagine laying a ski flat in an empty parking lot. If you were to trace one side of the ski, you'd get a concave arc along the ski's sidecut. Continue the arc around the parking lot into a circle. The ski's sidecut dictates how big the circle will be. The deeper the sidecut, the smaller the circle. The smaller the circle, the smaller the turning radius of the ski, and the tighter the turns it will make. In general, to qualify as a super-sidecut ski, the radius must be under 30 meters -- the Elan SCX, to take an extreme example, has a radius of nine meters. Most of the new super-sidecut skis have radii between 10 and 24 meters, while the radii of traditional skis average between 33 and 40 meters.Because a ski needs to be at least 60 millimeters wide to support a boot, manufacturers have widened the tips and tails of the skis to get the really extreme sidecuts. The Elan SCX is 115 millimeters across the tip, 112 millimeters across the tail, and 60 millimeters under the boot. "It's the narrowest ski ever made, and the widest ski ever made, all in one," says Bill Irwin of Monark Sporting Goods, Inc., of Burlington, Vermont, the US distributor for Elan.This hourglass design enables a skier to set an edge and turn much more easily and quickly than on conventional straight, narrow skis. Since the tip and tail are fat, when the skier rolls them onto an edge, the edge digs into the snow, and the middle of the ski bends down the hill until it finds the snow, shaping the ski into an arc. Translation: one perfectly carved turn. You can carve a turn with a conventional ski, but to do so requires a feel for weight-shifting that comes from years of experience on the slopes. With these new skis, even an inexperienced skier can set a pair of skis on edge and start carving. "It takes a lot of skill out of turning the ski," New Hampshire ski coach Chip Cochrane says."There's no more up and down," Womack adds. "It's all lateral. Just keep your head low and move your goggles straight across the ski. You're just tilting your feet from side to side, big toe to little toe, big toe to little toe."So what's the big deal with being able to carve a turn?"The feeling you get when you get a ski on edge, locked into a pure carved turn, is like no other feeling in skiing," says Womack. "Most people on traditional equipment never experience that feeling. It took me 15 years to make a good carved turn. It's a high-level move and sensation, right up there with all the other good feelings in life. In fact, I've heard people say it's the next best thing to sex."And that's what the hype over the new skis is all about: helping beginner and intermediate skiers experience the sensory rush once known only to expert skiers. "A carved turn is very hard to do," Cutts says. "The new skis have brought it down to the very beginner."Although it's commonly believed that this new design in ski technology was influenced by the hourglass shape of snowboards, it wasn't. Instead, like most innovations in ski technology and equipment, the new design came out of the racing world."One of the offshoots of this racing experiment was that some of the racers' wives and girlfriends also got on the skis. They started zipping around the hill, and having a real blast on them," Irwin says. "Everybody was paying so much attention to the race course, they weren't watching the wives and the girlfriends. It didn't hit them until afterwards that the ski had a much wider range of capabilities than the company had first thought."In just a little more than two years, the fat-tipped, narrow-waisted skis have captured more than 50 percent of the US ski market. And that number would be higher if ski shops hadn't sold out of them last year. Industry observers predict the skis will be on the feet of 75 percent of US skiers by season's end."Straight skis will be reserved for very specific purposes -- moguls, downhill," predicts Cutts.And ski areas, stuck for years in a flat market, are so enthusiastic about the new skis that they're replacing their entire rental inventories with them, and putting all of their ski instructors on them. Anybody learning how to ski this winter will learn on hourglass skis. "They're the future of skiing," says Bob Harkins, vice-president of skiing services at Sunday River, Maine.Ironically, although the new ski was born of racing, its success in the showroom all but eclipsed its function as a racing product, making the hourglass skis an almost exclusively consumer-driven phenomenon. That is, until the end of last season, when a so-so racer from New Hampshire named Bode Miller stepped onto a pair of super-sidecuts and blew away his competition. He won his first race at the Junior Olympics by 2.3 seconds and his second by 2.8 seconds, extraordinary margins of victory in the hundredths-of-a-second sport of downhill skiing."I've heard it called the biggest breakthrough in ski-racing history," says Cochrane, who coaches Miller. "These skis can cut such a tight turn you can run very direct at the gates and pull off turns you couldn't do on regular skis. They're going to change the whole sport of ski racing. Racers are going to need these skis just to get down the tighter, turnier courses that are going to be set in the future because of the skis."There are, of course, kinks to be worked out. Given that it's so easy to carve a turn, experienced skiers who are used to manipulating their old skis with what Irwin calls "gross movements and exaggerated patterns" can overdo it. "Because the ski turns so quickly, it does have a tendency to hook across the hill," Cochrane observes. "A lot of racers have found it a little slower at first, until they compensate for the overturn by releasing the ski a little sooner. They don't have to hold the edge as long as they used to. When racers realize they can release the ski down the hill as they're coming across the fall line, the ski will run clean arcs down the hill in a cleaner line."American consumers may be snapping up the new skis as quickly as they can find them, and racers rediscovering what they already helped to invent, but European skiers have barely begun to tune into the new technology. The popularity of the new skis has been confined almost entirely to America -- an ironic twist that has actually held back their growth in the States, since most skis are manufactured in Europe. American distributors are only just now convincing their parent companies to up production rates.Nevertheless, you can demo and rent the new skis almost anywhere. The lower your ability level, the softer a ski you'll want (this doesn't have anything to do with the sidecut, just the flex of the ski). Because the shaped skis are so stable, most people ski them shorter than more conventional skis. They retail for anywhere from $300 to $650 a pair.