Alpine skiing is the sport of sliding down snow-covered hills on skis with fixed-heel bindings. It is also commonly known as downhill skiing, although that also incorporates different styles. Alpine skiing can be contrasted with skiing using free-heel bindings; ski mountaineering and nordic skiing – such as cross-country; ski jumping; and Telemark. Alpine skiing is popular wherever the combination of snow, mountain slopes, and a sufficient tourist infrastructure can be built up, including parts of Europe, North America, Australia and New Zealand, the South American Andes, and East Asia.
Alpine skiing began as a club sport 1861 at Kiandra in Australia and a number of similar clubs in North America and the Swiss Alps. Today, most alpine skiing occurs at a ski resort with ski lifts that transport skiers up the mountain. The snow is groomed, avalanches are controlled and trees are cut to create trails. Many resorts also include snow making equipment to provide skiing when the weather would otherwise not allow it. Alternatively, alpine skiers may pursue the sport in less controlled environments; this practice is variously referred to as ski touring, backcountry skiing, or extreme skiing.
In competitive alpine skiing races four disciplines exist: slalom, giant slalom, super giant slalom, and downhill. Slalom ski races have courses that require short tight turns, whereas giant-slalom races have courses which are set with more widely spaced turns. Super-giant slalom and downhill have few turns, the courses have gates spaced widely apart and skiers often reach 100 km/h.
If one drops a ball at any given point on a ski run, the ball will be pulled down the hill by gravity and follow a path of least resistance known as the "fall line". A skier following the fall line will reach the maximum possible speed for that slope, which is often dangerously fast even on relatively shallow hills. A skier with their skis pointed perpendicular to the fall line, across the hill instead of down it, will not move at all. The speed of descent down any given hill can be controlled by changing the angle of motion to the fall line, skiing more across the hill rather than down it.
However, as the ski runs are generally of finite width, for any angle other than directly down the fall line, the skier will eventually move sideways to the edge of the run. At this point the skier must turn around and continue the decent in the opposite direction. In theory, a run down the hill would consist of straight sections across the hill, followed by sharp turns to the complementary angle, as if the skier is being reflected from the edges of the run.
Downhill skiing technique focuses on the use of turns to smoothly turn the skis from one direction to another. Additionally, the skier can use the same techniques to quickly turn the ski away from the direction of movement, generating skidding forces between the skis and snow which further controls the speed of the decent. Good technique results in a flowing motion from one decent angle to the opposite one, adjusting the angle as needed to match changes in the steepness of the run. This looks more like a single long series of S's than turns followed by straight sections.
This skier is performing a right turn using the classic stem-Christie technique. The left (downhill) ski has been stemmed out from the body, and their weight shifted onto this ski. This drives the inside edge into the snow, generating forces to their right (uphill). Note that the weighted ski is on-edge and forming an arc; if both legs were parallel the skis would begin to smoothly carve.
Generally there are two main forms of turns used in downhill skiing. The oldest, and still common, is the concept of "stemming", pushing the front ("tips") or rear ("tails) of the skis sideways from the body so they form an angle to the direction of travel. In doing so, the ski pushes snow forward and to the side, and thus by Newton's third law, the snow pushes the skier back and to the opposite side. The force backwards directly counteracts gravity, and slows the skier. The force to the sides, if unbalanced, will cause the skier to turn.
The most basic form of stemming is the snowplough turn taught to first-time skiers. In this technique, the skier uses their lower legs to angle the skis outward at the tails and in at the tips, forming a shallow angle between the ski and upper body. The two skis are angled in opposite directions, forming a V-shape. In this position, the sideways force from one ski is balanced by the opposite sideways force of the other, leaving no net turning forces. However, both skis are creating backward forces, which add together and create significant drag, keeping speeds slow. To turn, pressure against one of the skis is relaxed so the snow pushes it back towards the body. This lowers the turning force on this side, thereby allowing the other ski to dominate and turn the skier toward the straightened ski. The turn is stopped by forcing this ski out again. This technique is simple and extremely powerful, however, it is also quite tiring as the skier has to keep the skis in position against the inward-directed force of the snow. It is very difficult to use on steeper slopes or higher speeds.
Stemming is also the basis of one of the most common types of downhill techniques, the Stem Christie. In this case the skis are normally kept parallel to each other, and to initiate a turn, only one ski is forced away from the body. This creates the same general position as the snowplough, and the same forces cause the skier to turn. However, as the skis are pointed parallel between turns and do not have to be pushed against the snow, the total workload is greatly reduced. And as the drag force is only generated during turns, this technique results in faster speeds. Whereas a snowplough might safely be used directly down the fall line of a given hill, a Christie on the same hill would result in higher speeds, and skiing this technique normally requires the skier to turn across the fall line almost constantly.
The ultimate development of the stemming technique is the parallel turn, a name that is no longer descriptive. In the classic parallel, the basic turning forces are generated the same way as the stem Christie or snowplough. However, the forces are applied to both skis at the same time, so they remain parallel to each other as they rotate. When rapid parallel turns are quickly linked together, the upper body remains pointed down the fall line, and the lower body and skis are alternately driven into the snow in one direction and then the other. This was considered the height of good technique during the "hot dogging" era from the 1970s into the 1980s.[1]
This skier is in the middle a high-performance turn during a slalom race. The arced shape of the ski can be seen, especially on the outside ski (right side of the image). Snow being ejected from under the ski illustrates that skidding is taking place.
A different form of turn is the "carve". Carving is based on the shape of the ski itself; when the ski is rotated onto its edge, the pattern cut into its side causes it to bend into an arc. The contact between the arc of the ski edges and the snow naturally causes the ski to want to move along that arc. Starting a carved turn simply requires the ski to be rotated onto its edge, which can be accomplished through small movements of the hips and knees. This motion is very easy to apply to both skis at the same time, and carving is a naturally parallel technique. Carving turns are generally much smoother and longer than stemming, and keep the skis along the direction of travel as opposed to angled across it. Both of these reasons means that carved turns require far less effort than stemming for the same given amount of control over the decent. However, the technique is not simple to learn, at least before the introduction of "shaped skis" in the 1990s. Since that time, it has become increasingly common to teach carving as a form of parallel skiings, as opposed to the "classic" parallel technique.[2]
Modern downhill technique is generally a combination of carving and skidding, varying the ratio between the two when rapid control over the turn or speed is required. However, pure carving and pure stemming are used in certain circumstances. Pure carving is a useful technique on slopes of moderate steepness and smooth snow - "groomer carving" is widespread and there are skis dedicated to this style. Likewise, competitive mogul skiing remains an almost pure parallel Christie technique, although the turn initiation is aided by the moguls themselves.
Alpine skiing evolved as a specialization on the general sport of skiing during the late 19th century. In this era before ski lifts, all skiing requires some cross-country, some uphill climbing, and some downhill skiing. Equipment during this era was largely similar to modern cross-country gear - a normal leather boot was fastened to the ski at the toe, allowing the heel to rise off the ski and allow striding motions. During the 1930s, the Kandahar binding was introduced, which could be locked down at the heel for the downhill portions. The Kandahar remained in widespread use until the 1960s.
As more and more skiers took up the sport, especially in the 1950s, broken legs became all too common. Dr. Richard Spademan saw 150 spiral fractures pass through his emergency department near Squaw Valley in three days, an event that led to the development of the Spademan binding. By the early 1950s, several "safety bindings" were on the market that allowed the ski to come off when the ski twisted to the side. This helped reduce the incidence of spiral fractures, but the lack of standardization in measurements and the always-changing mechanical interface with leather boots make these less than foolproof.
In 1950, Howard Head introduced the Head Standard ski. This consisted of a conventional wooden ski sandwiched between two thin layers of aluminum. When the ski was rotated on-edge, the aluminum sheets prevented the wooden core from twisting longitudinally, and kept much more of the ski's edge firmly pressed into the snow. This so dramatically improved turning performance that it was referred to as "The Cheater", because it allowed even beginners to "cheat" their turns and look like pros. A further advance around 1960 replaced the metals with fibreglass, which improved the "springiness" of the skis and made them much more lively over bumps. The Dynamic VR-17 took this process to its modern conclusion in the late 1960s, when they introduced the torsion box design, which further improved longitudinal stiffness.
The evolution of torsional stiffness in skis allowed increasing control over the edging, and thus continued to improve the amount of carving relative to skidding through the turn. However, this evolution also demanded more of the skiers effort to be put into rotating the skis onto edge, as opposed to forcing them to rotate tip in or out. A true carving turn was not generally possible, because the lateral motion of the leg would not be transmitted to the ski through the ski boots of the era. These were generally cut low, just over the ankle, and soft laterally, both of which limited the amount of sideways turning force that could be applied.
In the winter of 1965/66, two new ski boots made of plastic came to market. Compared to leather designs, the Rosemount and Lange boots dramatically increased the amount of lateral stiffness, and in turn, the amount of edging control over the ski. Additionally, the plastic did not change shape over time or when it got wet. This allowed the bindings to be much more closely matched to the fit of the boot, and offer dramatically improved performance. For the first time, safety bindings were no longer looser than cable bindings, and rapidly took over.
By the early 1970s, fibreglass torsion-box skis about 200 cm long, plastic boots rising half way to the knee, and safety bindings of various construction were universal. Wooden skis, leather boots and cable bindings disappeared almost overnight, and were generally gone by 1972. Technique developed, but the sport remained little changed between this time and the 1980s. The only dramatic changes during this period were in form; the rear-entry ski boot was common during the 1980s but became unpopular and disappeared by the early 1990s, and Salomon's introduction of the monocoque ski design led to widespread use of the "cap ski", different only in that it was cheaper to produce.
By 1990, the sport was essentially the same as it was in 1975. Ski design was effectively at a dead end, and many changes in material or construction technique were largely for marketing. The introduction of snowboarding captured the imagination of a younger generation, to whom skiing appeared moribund. By the mid-1990s, many ski hills were dominated by boarders, and their ability to do stunts in terrain parks.
A major change took place after the introduction of the Elan SCX ski in the early 1990s. The SCX was the first widely available "parabolic" ski, which dramatically improved carving performance. It required no real changes in construction, only the designer's desire to experiment with more radical designs. By 1995, practically every ski produced had more or less "shaping", and for a time, carving became a sport onto its own. A similar change occurred with the "rocker" design, which bends the ski into a banana-like shape, as opposed to the classic bow-like shaping with the tips and tails pressed down and the center raised. Today, almost all skis include both of these design notes, further improving the ability of the ski to be smoothly carved in a wider variety of conditions and terrain. The introduction of twin-tip ("park") skis allowed them into the terrain parks, where they are now common.
Ski racer competing in a Giant Slalom race
Various Alpine skiing competitions have developed in the history of skiing. Broadly speaking, competitive skiing is broken up into two disciplines: racing and freestyle.
Racing involves making fast turns around gates in an attempt to attain the fastest overall time down one or two runs of a race course by having the tightest line possible. Elite competitive skiers participate in the annual World Cup series, as well as the quadrennial Olympic Games and the biennial World Championships. Slalom (SL), giant slalom (GS), super giant slalom (super-G), and downhill (DH) are the four racing disciplines. Slalom is the most technical discipline and has the shortest turns with distances ranging from 6 to 15 metres apart. It has speeds that can reach 35 km/h. Downhill is the fastest, where speeds can exceed 140 km/h, showing the clear distinction between the two disciplines. The Giant slalom event is also considered a technical event with medium sized turns and the Super-giant slalom considered a speed event, as similar speeds are reached as in the downhill discipline though jumps are provided. There is also a "Super Combined" event that includes one downhill run and one slalom run in a single day. In 2004, the FIS (Fédération Internationale de Ski) introduced a new event to the World Cup calendar called the super combined, or super combi, consisting of one shortened downhill run and just one slalom run. That year, the FIS also introduced an Alpine team racing event at the World Championships in Bormio, Italy. Ski racing is controlled by a set of rules which are enforced by FIS. These rules include such things as regulation ski sizes, sidecuts, boot heights, binding risers and other regulations such as limitations to chemical substances found in winning racers as well as many other things which all ensure one particular skier has no advantage over another. In 2008, these regulations were changed in order to make it harder for racers to complete a race course. Some changes included increasing the minimum ski length and also the sidecut which makes the ski turn less tightly.In 2008 ski lengths were increased as it was found by physiotherapists that the shorter skis combined with the constant knee jerking movements were considered unnecessarily harmful to racers knees due to the turning radius of the skis (especially the slalom skis) therefore the F.I.S made the minimum ski length for women in slalom 155 cm and men 165 cm. Other size minimums were put in place in the other three events.
Freestyle skiing incorporates events such as moguls, aerials, and sometimes "new-school" events such as halfpipe, big air, slopestyle, and skiercross. Together with extreme skiing, new-school freestyle skiing is also sometimes known as freeskiing. Until relatively recently, freestyle competitions also included an event called ballet, later renamed "acro-ski".
In addition to racing and freestyle, other types of Alpine skiing competitions exist. One discipline administered by the FIS but not usually considered part of racing is speed skiing, in which competitors strive to achieve the highest total speed in a straight line, with no gates or turns. Numerous non-FIS competitions have emerged over the years. More traditional events include gelandesprung jumping (ski jumping for distance on Alpine equipment), and "powder 8" contests; among the more recent introductions are "big mountain" or "extreme skiing" contests, in which athletes start at the top of a mountain and ski a route down that involves wide, fast turns as well as cliff drops. The competitors are judged on the technical difficulty of their routes and any tricks they perform on the way down the hill.
Ski competition rules and scheduling are managed internationally by the International Ski Federation (FIS) based in Switzerland. Each participating nation worldwide is represented by a national association that manages the sport in that respective nation.
Most organized skiing competitions are dependent on a team of Race Officials and course workers who plan, organize and run the events. Alpine ski races are usually organized by a Race Organizing Committee (ROC), led by a Race Chair. Race Officials include the Chief of Race, chief of course, starters, timers, gate judges, referees, a jury and others who organize the event and ensure it is run safely and according to governing body rules. Under the leadership of a Chief of Course, course workers erect safety systems (usually nets), prepare and maintain the surface of the race course, erect and maintain other equipment such as a start tent, a finish area and the gates through which competitors must pass, and remove any fresh snow that may fall during the event. A FIS World Cup downhill, for example, requires a team of several hundred course workers that may spend over two weeks preparing a course prior to a week of racing, during which the course workers will continue to maintain the course. Race Officials and course workers are usually volunteers, but may include paid staff and, in some European countries, members of the military. Most regular venues of major Alpine ski races have a local ROC which remains in place from year to year. An example of an organization of volunteer course workers are the Whistler Weasel Workers.
In most ski resorts, the runs are graded according to comparative difficulty so that skiers can select appropriate routes. The grading schemes around the world are related, although with significant regional variations.
Typically, grading is done by the resort, and grades are relative to other trails within that resort. As such, they are not classified to an independent standard; although they are likely to be roughly similar, skiers should be cautious about assuming that grades in two different resorts are absolutely equivalent.
A typical sign indicating ski slopes and their difficulty
In North America, a color–shape rating system is used to indicate the comparative difficulty of trails (otherwise known as slopes or pistes). Australian ski slopes also share the same rating system.
Ski resorts assign ratings to their own trails, marking a given trail according to its relative difficulty when compared with other trails at that resort. Although slope gradient is the primary consideration in assigning a trail rating, other factors come into play — including trail width, normal snow conditions and whether or not the resort regularly grooms the trail.
Ski trail difficulty ratings in North America
| Trail Rating |
Symbol |
Level of difficulty |
Description |
| Green circle |
 |
Easiest |
The easiest slopes at a mountain. Green Circle trails are generally wide and groomed, typically with slope gradients ranging from 6% to 25%[3] (a 100% slope is a 45 degree angle). |
| Blue square |
 |
Intermediate |
Intermediate difficulty slopes with grades commonly ranging from 25% to 40%.[3] These slopes are usually groomed. Blue Square runs make up the bulk of pistes at most ski areas, and are usually among the most heavily trafficked. |
| Black diamond |
 |
Advanced |
Amongst the most difficult at a given mountain. Black Diamond trails tend to be steep (typically 40% and up)[3] and may or may not be groomed, though the introduction of snowcats has made the grooming of steep slopes both possible and more frequent. |
| Double black diamond |
 |
Expert Only |
These trails are even more difficult than Black Diamond, due to exceptionally steep slopes and other hazards such as narrow trails, exposure to wind, and the presence of obstacles such as steep drop-offs or trees. They are intended only for the most experienced skiers.
This trail rating is fairly new; by the 1980s, technological improvements in trail construction and maintenance, coupled with intense marketing competition, led to the creation of a Double Black Diamond rating.
|
| Variations |
 |
Various |
Variations such as doubling a symbol to indicate increased difficulty, or combining two different symbols to indicate intermediate difficulty are occasionally used, as is often in Colorado at Winter Park resort and other Colorado ski resorts. One example is a diamond overlapping a square to indicate a trail rating between a Blue Square and a Black Diamond. Many resorts throughout Colorado use a double diamond with an "EX" in the center to mark a run with extreme terrain, even more difficult than a double diamond. Other resorts, such as Smugglers' Notch, Vermont, Le Massif, Quebec, and Mt. Bohemia, Michigan, use triple black diamonds. The combination of symbols is comparatively rare at U.S. ski areas; most ski resorts stick to the standard 4-symbol progression (with the exception of the common EX runs in Colorado).
Non-standard symbols for standard ratings may be encountered at some ski areas. Bogus Basin, a resort near Boise, Idaho, uses orange diamonds on trailheads for trails that are indicated in the resort's Alpine Guide as double black diamonds.[4]
|
| Terrain parks |
 |
Various |
Terrain parks are whole or portions of trails that can offer a variety of jumps, half-pipes, and other special "extreme" sporting obstacles beyond traditional moguls. The trails are typically represented by an orange rectangle with rounded corners.
Usually, the terrain park will carry its own trail rating, indicating the level of challenge. A terrain park with a Black Diamond or Double Black Diamond rating would contain greater and more challenging obstacles than a park with a Blue Square rating.
|
Red slope in Park Snow
Donovaly, Slovakia
Sign for a black expert slope in
Flaine, France
In Europe, pistes are classified by a color-coded system. The actual color system differs in parts for each country - in all countries blue (easy), red (intermediate) and black (expert) are used. Shapes are not always used - sometimes all ratings are circles as being defined in the basic rules of the German Skiing Association DSV.[5] The three basic color codes of the DSV have been integrated into the national standards DIN 32912 in Germany and ÖNORM S 4610 f in Austria. The ratings are:
- Green
- (Spain, France, Scandinavia, UK, Poland) Learning or Beginner slopes. These are usually not marked trails, but tend to be large, open, gently sloping areas at the base of the ski area or traverse paths between the main trails. Can sometimes be marked as a Green circle.
- Blue
- An easy trail, similar to the North American Green Circle, and are almost always groomed, or on so shallow a slope as not to need it. The slope gradient shall not exceed 25% except for short wide sections with a higher gradient. Sometimes described as a blue square.[5]
- Red
- An intermediate slope. Steeper, or narrower than a blue slope, these are usually groomed, unless the narrowness of the trail prohibits it. The slope gradient shall not exceed 40% except for short wide sections with a higher gradient. Sometimes marked as a red rectangle.[5]
- Black
- An expert slope. Steep, may or may not be groomed, or may be groomed for moguls. Black can be a very wide classification, ranging from a slope marginally more difficult than a Red to very steep avalanche chutes like the infamous Couloirs of Courchevel. France tends to have a higher limit between red and black. Sometimes marked as a black diamond.
- Double or triple black diamond
- (Scandinavia) Very or extremely difficult piste.
- Orange
- (Austria, Switzerland, certain other areas) Extremely difficult.
- Yellow
- In recent years, many resorts reclassified some black slopes to yellow slopes. This signifies a skiroute, an ungroomed and unpatrolled slope which is actually off-piste skiing in a marked area. Famous examples are the Stockhorn area in Zermatt and the Tortin slopes in Verbier. In Austria, skiroutes are usually marked with orange squares instead.
Alpine slope classification in Europe is less rigidly tied to slope angle than in North America. A lower angle slope may be classified as more difficult than a steeper slope if, for instance, it is narrower and/or requires better skiing ability to carry speed through flatter sections while controlling speed through sharp hairpin turns, off-camber slope angles or exposed rock.
Japan uses a color-coded system, but shapes do not usually accompany them. Some resorts, mainly those catering to foreigners, use the North American or European color-coding system, adding to the confusion. When in doubt, check the map legend. The usual ratings are:
- Green
- Beginner slopes. These are usually near the base of the mountain, although some follow switchback routes down from the top.
- Red
- Intermediate slopes. At most ski areas in Japan, these constitute the majority of the slopes (40% to 60%,[citation needed] depending on how the slopes are accounted).
- Black
- Expert slopes. These are the steepest and most difficult slopes at the ski area. The difficulty of these compared to like-classified slopes at other ski areas is heavily dependent on the target audience.
Japan has more than 1000 ski areas (115 in Nagano Prefecture alone),[6] many of them small and family-oriented, so comparisons between slope classifications in Japan and "equivalent" slopes in Europe or North America are minimal.
This
terrain park begins with three jumps, each with a variety of entries.
Skiers and snowboarders can encounter a wide range of snow and weather conditions, in part due to the location of specific resorts and global weather patterns at the time. Natural snow ranges in consistency from light and powdery to dense and heavy, depending upon atmospheric conditions. Snow is often measured by moisture content. Some areas of the United States' Rocky Mountains, for example, can receive considerable amounts of snow with moisture content as low as three to five percent; in the Northeastern United States and the Alps, moisture content is more typically 15 percent or more. Snow made by mechanical snowmaking often has moisture content of 35 percent or more.
Temperatures play a critical role in snow moisture content, but other atmospheric conditions are also relevant. Air currents and other factors determine snow crystal shape; obviously, the farther apart given snow crystals are, the more air is contained in the newly settled snow, resulting in lower net moisture content in a given volume of snow. Snow produced mechanically typically has high relative moisture content and low amounts of loft because the crystal structure resembles small, dense pellets. Even the fluffiest snow has mass, and snow typically settles under its own weight after time. This is one reason why untouched snow measuring 20 cm on the day it falls might be measured at 15 cm the day following. Snow is also subject to sublimation — a process by which water can go directly from a frozen state to a gaseous state without first melting. It is this same process that ultimately makes ice cubes shrink in a freezer. There are other factors that impact snow beyond its moisture content and crystal shape, however. Snow is impacted by wind, sunlight, skier traffic, ambient air temperature, relative humidity and grooming equipment; all of these factors combine to change snow crystal shape and density over time.
Some of the common conditions include:
- Powder
- Light, fluffy snow, found during and immediately after snowfall. Skiing and snowboarding in deep powder snow is a favorite among skilled, experienced skiers and snowboarders; sometimes known as "powderhounds" hunting for the next big dump. Because Western snow generally has a lower moisture content, western powder is lighter and easier to ski than heavier eastern powder. Utah and Colorado snow is especially known for being extremely light and dry as well as a lot of snow found in New Zealand.
- Packed Powder
- Packed powder is compressed powder that is formed after the snow is groomed. Whereas hard pack (see below) is extremely dense and hard to ski on, packed powder is slightly less dense and able to support skis without sinking. This makes it very easy and fun to ski on.
- Chowder
- Chopped up powder. Powder that has fallen in the prior few days and remains light and fluffy but has been skied or tracked up.
- Crud
- Once powder snow settles and becomes tracked up by skiers and snowboarders it firms or freezes into texture that is challenging and usually undesirable. Crud may contain "chicken heads", balls of frozen snow.
- Groomed or corduroy
- Snow that has been tilled by a grooming machine. This snow condition is favored by beginners and the majority of recreational skiers, in that it tends to be relatively forgiving, easy to turn upon, and requires less skill to negotiate than powder snow. The name comes from the look of the snow after it as groomed, as it looks like corduroy fabric.
- Granular snow
- Snow with large crystals, i.e. small pellets. Depending on sun and temperature conditions, it may be wet granular snow — meaning that there is a considerable amount of unfrozen water in it, or loose granular snow, which has no unfrozen water. Wet granular snow will form a snowball; loose granular snow will not. Wet granular conditions are often found in the springtime. Loose granular conditions are generally produced when wet granular snow has re-frozen and then been broken up by snowgrooming apparatus.
- Corn snow
- The result of repeated daily thaws and nightly re-freezing of the surface. Because of the thaw-refreeze cycle, snow crystal shapes change over time, producing crystal shapes somewhat akin to wet granular, but larger. True corn snow is a delight to ski or ride once it softens in the afternoons.
- Ice Cookies/Snow Snakes
- Similar to corn snow but much larger. Snow has melted, re-frozen, and been "skiied out", creating hard snowballs of ice- sometimes as big as tennis balls. Skiing in these conditions can be tricky and sometimes dangerous.
- Slush
- When the sun heats the snow and causes it to become very wet and very heavy. Skiing in these conditions can be difficult.
- Ice/Hard-Pack
- Skiers and snowboarders typically regard any snow condition that is very hard as "ice". In fact, true ice conditions are comparatively rare. Much of what is perceived to be ice is actually a frozen granular condition — wet granular snow that has refrozen to form a very dense surface. Telling the difference is comparatively easy; if one can get a ski pole to stand up in it, the surface is likely to be more of a frozen granular surface than an icy one — and while it is certainly not as enjoyable as many other snow conditions, skilled skiers and snowboarders can successfully negotiate it. In fact, ice is a preferred condition among racers, in that the surface tends to be quite fast and race course conditions tend to remain more consistent during the race, with fewer ruts developing on the course. Another form of icy condition can be found at higher elevation resorts in the Rocky Mountains and in Europe; direct sunlight can melt the top layers of snow crystals and subsequent freezing produces a very shiny, slick surface.
- Crust
- A crust condition exists when soft snow is covered by a harder upper layer upon the surface. This crust can be created by freezing rain (precipitation formed in warmer upper levels of the atmosphere, falling into a temperature inversion at which surface temperatures are below freezing, and freezing on contact with the ground), by direct sunlight, and by wind loading which packs down the upper layers of the snowpack but leaves lower layers more or less unaffected. Crusts are extremely challenging conditions.
- Dust on crust
- A trace of new snow on top of crust. Undesirable.
- Spring conditions
- A catch-all term ski areas use to describe conditions when numerous different surface types can be found on the mountain — usually in the later part of the season, although the term is sometimes used during an extended midwinter thaw. The term also generally reflects the presence of bare spots and/or areas of thin cover. With spring conditions, the snow is usually firm in early morning (even reaching frozen granular status if left ungroomed), breaking a softer corn or wet granular surface mid-day, and is often very soft and mushy in afternoon (many skiers refer to this type of snow condition as "mashed potatoes", due to its heaviness). In some instances when the snow is untracked, sun baked, slightly dirty, with the consistency of a snow cone, it is called "tecate powder". The speed with which conditions change on a given spring day is directly related to the exposure of the slope relative to the sun. In the northern hemisphere, east- and south-facing slopes tend to soften first; west-facing slopes generally soften by mid-day. North-facing slopes may hold on to their overnight snow conditions throughout the day.
- Windblown
- A type of snow that forms when powder isn't skied on for a long period of time. It is essentially powder past its expiration date. The consistency is that of a thick and "sticky" powder, that provides lots of resistance; it often is covered by a crust of hard packed snow. It is prone to happening in large, open areas where there is little shelter from the wind. Its appearance often fools inexperienced skiers to believe it is fresh powder.
- Variable
- "Variable" simply means that all types of snow can be on the mountain, ranging from hard pack to crud. It is usually a secondary classification.
Chemicals can be applied to the snow surface in order to harden the course. The most common chemicals used are sodium chloride, calcium chloride, urea, ammonium nitrate, and potassium nitrate. This "salting" is done mostly when the snow is wet and slushy. When a race course is salted, the salt crystals break up into ions. These ions lower the freezing point of the snow, which hardens the surface. This provides a dense layer of snow with a consistent surface throughout the course, making the race more fair for athletes running later in the race.
Two important factors that determine whether salt will work are crystal structure and moisture. Crystals that are too sharp will prevent the deep penetration of the salt into the snow. Crystals that are too round lack flat surfaces that can bond tightly to adjacent crystals. The snow also needs to have a moisture content of around 60%. Salting a race course works best when the weather is sunny and warm. Salting may also work when it is raining, since the rain adds moisture to the snow. In general, salt will not harden the snow if it is cloudy and just above freezing.
Salting is typically only done in slalom and giant slalom events. It is important to salt the apex of the turn especially well, because that is the part of the turn when the skier exerts the most pressure on the snow. Speed events (downhill and super giant slalom) have a larger surface area, making salting expensive; the high speeds of these events also make salting potentially dangerous.
- ^ An excellent film of the classic parallel technique can be found in the YouTube video "Classic Short Radius Turns". Note that the skier's upper body remains pointed down the fall line, and their body moves only a small amount from side to side. Turns are initiated at the tip, and skidding progressively develops - note the amount of snow being thrown off the back of the ski as the turn develops. The skis can be seen to bend into arcs, but these are relatively modest.
- ^ A basic explanation of the carving concept can be found in this "Carving Ski Lesson". Note that the skier's body rotates along the turn, and that snow is kicked up, when it is, along the entire length of the ski. In this companion video, "Intermediate Ski Lesson #4.1 - Turn Shape", the difference between the classic skidding turn and carving is directly illustrated. Carved turns are now often used as a training technique for even the first-time skier, an example of this method can be found in the YouTube video on "Teaching the Pure Carved Turn".
- ^ a b c "Appendix G: Mountain Specifications Summary, Draft Environmental Impact Statement for The Timberline Express Proposal" (pdf). USDA, U.S. Forest Service, Mount Hood National Forest. March 2005. pp. 26. http://www.fs.fed.us/r6/mthood/projects/timberline-express/Appendices/Appendix%20G%20-%20Timberline%20Mountain%20Specifications%20Summary/Appendix%20G%20-%20Timberline%20Mountain%20Specifications%20Summary.pdf. Retrieved 2006-12-10.
- ^ Bogus Basin Mountain Recreation Area. 2010. Alpine Guide
- ^ a b c "Die Markierung von Pisten und Loipen", Deutscher Skiverband, Journal, 8. August 2005
- ^ Ski areas and resorts in Japan
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