Johan Porsby, 2007-10-26

Note from Bob Dill and Vince Rossano, May 11, 2012: The following is a comprehensive list of Swedish terms associated with ice.  The list was developed by Johan Porsby, a well-known Swedish student of the properties of ice, particularly as they pertain to skating.  While the terms are defined with a focus on skating, they  apply as well to most ice activities. this list demonstrates the considerable depth of understanding of ice and ice behavior that has been developed in Sweden. The following has been translated with Google Translate by Bob and reviewed and corrected by Vince. Vince has also taken the liberty of linking to pictures that can be found on the SSSK site.  Each ice word or phrase is followed, in parentheses, by a more-or-less literal translation of the term, and then by the definition.  Swedish terms are in italics.  Swedish terms defined elsewhere in the list are in bold italics. Editorial notes and comments are also shown in Italics. We have tried to stay true to Johan's wording and intent. He reminded us that many of the words do not have a one to one relation between English and Swedish and there are also geographical and cultural differences that create different viewpoints on the meanings.  If you find that any of the English wording misses the intent of the Swedish words, or if you discover any other errors, please get in touch.  The original document can be seen here. Additional discussion of many of these ice terms can be found elsewhere on the LakeIce site (the Glossary and the menu list on the right side of the page are good places to look)

After reviewing this translation, Johan suggested the following were the most useful words. In Isordlista these words are shown with underline and larger text.

  • Kärnis (black ice)
  • Stöpis (slush ice)
  • Sötis (fresh water ice)
  • Saltis (brackish or sea ice)
  • Vindbrunn(warm water hole)
  • Råk (pressure ridge)
  • Överis (shell ice)
  • Glasis (dry shell ice)
  • Vrakis (jumbled ice)
  • Tallriksis (Pancake ice)
  • Rutten is (rotten/well thawed ice)
  • Slukhål (drain holes)
  • Våris (spring ice)
  • Svinga (ice broken by large waves or, especially, ocean swells)

Isordslista (ice vocabulary): Glossary of common terms related to ice and ice phenomenon. The words are described based on how they are used in ice skating on natural ice, with a geographical focus on the conditions found in Sweden and Finland's inland and coastal ice. In other areas such as maritime or polar ice caps, the concepts may have a different meaning

Aktiv spricka (active crack): An open (wet) crack between the two plates that move relative to each other. An active crack is a warning signal that the ice may be starting to move and will eventually break up.

Ankaris (anchor ice) see bottenis

Avsaltning (desalination): Reduction of salinity  in older salt ice. The reasons are many. The unfrozen brine is dense and is in vertical pockets between the ice crystals. It can work its way down through the ice. Melt water can also help to flush out the salt from the ice. On cold ice, frost in salt pockets squeezes salt from the ice (both down and up). For the ice skater, the ice gets noticeably tougher and more heat resistant when the top ice layer is desalinated.

Blåis (blue ice): Freshly laid thin clear salt ice.  

Bottenis  (bottom ice): Most often referred to as "anchor ice", this is ice formed from frazil, which adheres to the bottom of a lake or river. The term includes ice that formed on the bottom or at great depths and then floated to the surface. It is common in strongly flowing waters and shallow archipelagos near the open sea. If anchor ice has enough buoyancy, it can break free and float to the surface and can carry with it frozen plants, rocks and other objects.  It is common for anchor ice to form during the night, and rise to the surface during the day when the sun's rays cause the ice to release from the bottom. May also be referred to as ankaris or grundis. [See photo.]

Bottenstöp (bottom slush): Slush that forms at the bottom of a layer of snow on the ice. See stöpning (formation of slush)

Bräckvattensis (brackish ice): Ice created from brackish water.  Considered Salt Ice. Water salinity plays a major role in ice formation. The reverse density gradient that occurs in fresh water below 4˚ C only occurs in brackish water with salinity below 2.5% (typical seawater is 3.5%). This gradient keeps the coldest water at the surface and facilitates the formation of ice on the surface of fresh water. The Baltic Sea is brackish water. The Stockholm archipelago has a salt content approximately 0.6%. In water with a salinity below 0.1% normal black ice forms and it is almost free of salt. See omvänd skiktning (reverse temperature gradient in water below 4˚C)

Bubbelvak (bubble hole): An artificial hole in the ice that is kept open by pumping air down into the water. The ascending bubbles entrain warmer deep water and bring it to the surface, which prevents ice formation. It is similar to a gas hole. Bubblers are common around marinas and docks. See gashål (gas hole).

Bågnad is (bent ice): Ice with a slightly bowl-shaped surface. It forms in thick ice in cold weather. The cold causes the upper surface of the ice to contract and form shallow bowls between contraction cracks. The colder the temperature, the greater the bend. This formation is a good sign that the ice is thick. The cracks can, however, be a tripping hazard for skaters.

Bärighet (carrying capacity): The ice's ability to bear weight such a skater. It is a combination of ice thickness and quality. Thin ice may have better carrying capacity than thick ice of poor quality.

Degenererad is (deteriorated ice): Ice which is thawing as a result of warm temperatures or solar radiation, causing significantly reduced strength.

Direkt skiktningen (direct stratification): Density stratification in a lake with warmer water closer to the surface during the summer. In fresh water, (in summer) the temperature at the bottom of a lake is 4º C or warmer. See also omvänd skiktning (reverse stratification) and språngskikt (thermocline).

Dränkstöp (soaked slush): Slush on the ice formed by the passage of water through the ice into snow on the surface. Dränkstöp is formed when the snow's weight is greater than the ice buoyancy, so that the upper surface of the ice is pushed down below the water surface. The water-soaked snow (slush) forms when water flows through cracks in the submerged ice. In salt water, saline slush is formed by a combination of saturating the snow and melting some of the snow by the salt content of the water. Slush can also form from rain falling on the snow as well as melting of the snow cover.

Dubbelis (double ice): Shell ice, i.e., ice composed of two layers with water or air in between. See överis (wet shell ice), glasis (dry shell ice), halvfruset stöp (half-frozen slush) and laminerad is (laminated ice).

Dyning (swells): Waves that are no longer driven by the wind. Swells are formed by a distant wind and come from the direction of the storm. The swell is made up of long smooth waves that are high in energy relative to wave height. Swells can carry long distances under the ice and give rise to wave-broken plates far from the ice edge.

Etsad (etched ice): Ice which has a pattern of grooves in the surface at the boundaries between the ice crystals. It often has a dry surface.  See krackelering[See photo.]

Frånflöde (outflow): Outlet of a lake

Fräthål (erosion hole): A hole formed when the ice is melted from below by water currents. Melting on the underside of the ice (see underfrätningen) is often very uneven, with holes or thin spots occurring in the ice. The spots that are thinned by erosion from underneath often appear as dark areas in the ice.  [See photo.]

Gasbubblor (gas bubbles): Bubbles of gas in or under the ice formed by gas released from bottom sediments. They often appear as white bubbles in dark ice. Gas bubbles may lead to a weakening of the ice, as the gas separates the ice from the underlying water, preventing the ice from getting thicker.

Gashål (gas hole): open hole in the ice caused by the gas released from the bottom. The stream of rising gas bubbles brings warmer bottom water to the surface, which prevents ice formation. See bubbelvak (bubbler-created holes).  [See photo.]

Genomstöpt (soaked through): Ice where the snow on top has transformed completely to soaking wet slush. The snow will then have a grayish color. The snow needs to be completely saturated as a prerequisite for slush ice (frozen snow slush) to start forming.

Glanskis (glossed ice): New, smooth black ice. Often referred to as clear ice that is unaffected by rain and snow.  [See photo.]

Glasis (glass ice): Dry shell ice-a variant of dubbelis (shell ice), glasis forms when puddles on the ice skin over and then drain through small holes before the puddle freezes completely. Dry shell ice occurs mainly in thick ice where the upper surface floats above the lake's water level. Dry shell ice often lasts for a long time since there is no water between the ice layers to freeze and join the top layer to the main ice sheet. It presents significantly less risk of tripping than wet shell ice (see överis), but large areas of this type of ice can make skating less enjoyable. [See photo.]

Grovkrackelerad (heavily-crackled ice): Clear ice with very large ice crystals, under the influence of near freezing temperatures or sunlight, so that the crystal boundaries are visible. It often develops a gray color. Grovkrackelerad ice is the type of ice which maintains the most strength in the spring. Nevertheless, in cold conditions, it has less strength than smaller grained ice. Note: the term 'crackled' refers to the many etch pits that form in the crystals away from the grain boundaries.  The etch pits are casued by internal melting of the crystal and they give the ice a gray color.

Grovkristallin kärnis (large-grained black ice): Clear ice with large ice crystals (with a cross section larger than about four inches). Ice with large crystals is formed primarily in moderately cold temperatures and when the water is calm but still relatively warm. As a rule, colder air and lower water temperatures produce smaller ice crystals. See also smalstavig kärnis. (small grain ice).

Grundis (ground ice) see bottenis

Halvfruset stöp (half-frozen slush): This occurs when a snow cover is fully transformed to slush, but has not frozen all the way down to the underlying ice. It forms a layered structure of crusty shell ice over slush on top of the main ice sheet. This surface can be strong in the morning, but as the temperature rises, the surface will break under body weight. It can be almost impossible to get around, and the risk of falls is high. Half frozen slush occurs frequently on snow ice in the Stockholm archipelago in the spring. This can significantly weaken the underlying ice and it can become very treacherous.

Halvstöpt (half-soaked): Snow that is not fully turned into slush. On the top of the snow it remains dry and white. The bottom tends to be more fully saturated slush. See also bottenstöp (a slush layer between the ice sheet and dryer snow on top) and genomstöpt (snow that has completely changed to slush)

Havsis (sea ice): Ice on the unprotected seas. It is often in motion and in floes separated from the coastal land-fast ice.

Havsråk (sea ice crack): A large crack or lead (see släppråk) in sea ice outside the protective archipelago, often big enough to sail a ship in. A havsråk that has frozen over can provide a long smooth passage through otherwise un-skateable rough or snow covered ice.

Hängmatta (hammock): The obvious deflection of thin ice when it is loaded by skaters. The ice can be easily broken by a wave formed by the deflection if the skating speed is too high. On salt water ice that has not been desalted, there is even more deflection at the same ice thickness.

Isbro (ice bridge): a string of good ice surrounded by open water. It can be formed around and between islands or in areas protected by wind and waves by islands. An isbro should be traveled on with caution. Wind, current, or swells can easily break up the ice bridge. Can also refer to an artificial bridge over ice. See also isrygg and isfärja.

Isfärja (ice ferry): An ice floe which can be used to ferry skaters across open water. The word can also refer to a ferry for cars across an open water channel (found on some ice roads in the Finnish archipelagos). [See photo.]

Isgräns (ice border): The border between the ice of different thicknesses or strengths. Ice edges are of great interest to skaters as the ice may be too thin to support a skater on one side of an ice edge. The timely detection of an ice edge and determining whether the ice on the other side of the edge is sufficiently strong, is one of fundamental skills of ice evaluation.  [See photo 1.]  [See photo 2.]

Ishävning, (ice heaving): Swells (waves), typically from the ocean. See svinga.

Iskant (ice edge): Where ice meets open water.  [See photo.]

Ismaximum (ice maximum): The time of year when the ice coverage has its largest extent. In the archipelago it normally falls quite late in the season, especially in good winter conditions. Ice sheet decline after the ice maximum is much faster than ice sheet growth.

Ispress (ice pressure): Ice pressing against the shore or an ice shelf. See also isskjutning. [See photo.]

Isrygg (ice ridge): A belt of strong ice over an area of weak ice. It can be created, among other ways, by isskjutning (ice pushing) or through the ice being reinforced when several layers are pushed on top of each other. A narrow isrygg can be dangerous; if it breaks you may find yourself far out on weak ice. Compare with isbro.

Isskjutning (ice pushing): Ice that moves or pushes against shore or an adjacent ice sheet. Weaker isskjutning is caused by thermal fluctuations that put pressure on the ice sheet. Heavy isskjutning is called isskruvning.  [See photo 1.]  [See photo 2.]

Isskruvning: (ice tightening): Very heavy isskjutning. Isskruvning is a powerful horizontal force on an ice sheet caused by friction between it and the wind or water flow in rivers. At sufficiently large force the ice may rupture and be broken into blocks, many of which end up under water. You are in imminent danger if you find yourself to be on the ice when and where this type of rupture occurs. You can easily be trapped or crushed by the large blocks of ice. In the past isskruvning was a real threat to seal hunters. Modern skaters have also been victims of dangerous isskruvning.  Lake Vättern is notorious for isskjutning even at moderate wind speed.

Issörja (ice slush): A viscous mixture of water and frazil, or water and snow.

Issörpa (ice mash): An accumulation of frazil (primarily in rivers)

Kalle, kallar ([idiomatic]): see landkalle

Kalvar (calves): An ice sheet that is shrinking due to pieces of it breaking off at the edge and floating away due to wind, waves or currents.  [See photo.]

Kompanjonspricka (companion crack): A crack that follows a group of skaters along their direction of travel. The leading end of the crack is clearly audible and is normally about ten feet forward of the group. Is often a good sign that the ice has a uniform thickness. In new black ice companion cracks occur at an ice thickness of around 5 cm. They also occur in salt ice.

Krackelering (crackling): Visible loosening of the crystal boundaries in ice. In warm conditions, a noticeable pattern forms on the surface of black ice as the crystal boundaries melt first. See vårkrackelering and värmekrackelering.

Krav (frazil): Small ice crystals a few millimeters in size which form in cold weather in turbulent water. Frazil is kept suspended in the water by turbulence. It forms in very cold weather when the water is supercooled to a greater depth. It occurs frequently in rivers with strong currents. Frazil can also form in the ocean where the surface is stirred up by the wind and waves, and, more rarely, in lakes. Frazil can be very sticky and clumps easily to itself and any surface. It can accumulate on the bottom of shallow areas where it forms anchor ice, or it can float to the surface where it forms a viscous slurry called "grease ice". This can then freeze together to form solid ice. See kravis.

Kravis (frazil ice): The ice formed from frazil (usually in flowing rivers and the sea). Kravis formed in salt water may have an especially high salinity, and hence, poor strength.  [See photo.]

Kärnis (kernel ice): "Black ice", i.e., ice formed when water in its liquid state freezes directly into ice (as opposed to stöpis, snöis and kravis formed by slush that freezes). Black ice formed from fresh water is very clear and transparent. It grows on the underside of an established ice cover and consists of columnar ice crystals that often extend through the entire thickness of the ice (as opposed to stöpis, snöis and kravis, which have small roughly spherical crystals). Ice crystal sizes range from a few millimeters to nearly one meter. Black ice is very strong and has good resistance to thawing. Ice with large crystals has the best strength retention in the spring.  Another term for this type of ice is "congelation ice".

Köldspricka (cold crack): Cracks formed when the ice is contracting in cold weather. These are usually dry with small gaps at the ice surface. Cold cracks are a sign that the ice is thick but they pose a risk of falls when skating if your skate drops into the crack.

Laminerad is (laminated ice): Ice that consists of several ice sheets that have been badly frozen together. Laminated ice is difficult to evaluate from the sound it makes when skating over it or probing it with a test pole. Also referred to as "laminatis" and "skicktad is" (layered ice)

Landfast is (landfast ice Ice that is firmly attached to shore (mostly on sea ice). See also landlös is.

Landkalle ([idiomatic]): [1]* Ice left on a beach. [2]* Ice along the shore, often tilted and a bit higher than the rest of the ice, which can provide skating trails along the beaches when the ice further out is not good for skating. It is formed by expansion of the ice when it warms, sea level change, or water that splashes onto the shore and freezes. See uppsvallad is. [See photo1.]   [See photo 2.]  *The division into two different senses is the editor's.  The Stockholm Ice Skating Club (SSSK) makes a distinction between the word "landkalla", which is a traditional Swedish word for ice piled up and left on a beach, fitting sense 1, and "landkalle", which is a word specific to skating terminology fitting sense 2 above.

Landlös is (landless ice): Ice that is near shore but not in contact with the shore. It usually occurs during mild weather, strong sun, or after the water level changes. See also strandbräcka. [See photo 1.]

Luftinnehåll (air content): The amount of air contained in slush, snow and salt ice. More air content usually results in ice with a lighter gray color. The higher the air content, the lower the strength and the more easily the ice softens in warm conditions. See also marängis (thawed small grain ice).

Långsvinga (long swing): Svinga, Long ocean swells which may travel a long distance into an ice sheet as much as several kilometers. (see also dyning)

Läbrunn (lee well): Persistent open water formed when the wind blows off shore or an old ice sheet. The wind pulls blows the surface water away from the edge, which in, turn draws up warmer water from the depths.  This can remove some or all of the old ice sheet and delay the formation of new ice.

Madrassis (mattress ice): A type of well thawed, medium crystal size ice that ice that deforms dramatically under load. The deformation looks a lot like what you see when standing on a mattress.   Madrassis is very unpredictable and should be avoided.  See also: Pipis 

Marängis (meringue ice): Slush ice with high air content and thus very poor strength. Marängis usually builds up at leads and wet cracks as blowing, dry snow sticks to wet snow made wet by water the snow wicks up from the crack.  Meringue ice is quite variable in strength and is unpredictable. The name refers both to the appearance and strength.

Mittspricka (center crack): A dry crack that occurs frequently in older ice, in the middle of a plowed path, channel or river. It is easy to catch a skate in these cracks, often resulting in a fall.  [See photo.]

Motstrålning (counter radiation): Heating of the water or ice by objects which reflect or radiate heat. Motstrålning can delay freezing and inhibit ice growth. Clouds, bridges and piers may often have this effect. Trees and steep banks can also suppresses ice growth in the same way.

Naturis (natural ice): Ice on lakes, seas and rivers without the influence of human improvement (snow removal, zamboni work or flooding the ice).

Nedråk (down crack): a down-folded ice sheet. It is formed when two ice sheets press against each other, and the main fold points downward. They occur most commonly on new salt ice. They are difficult to cross because the folded ice plates may lie deep below the surface. Furthermore, in many cases, the submerged plate may have melted away or been greatly weakened. Also called: nedvråk (also nervråk)  [See photo.]

Omspolad is (rewashed ice): Ice that has melted or been exposed to rain and then re-frozen. Omspolad ice is often smooth and even, but can be difficult to assess because the thick to thin edges and other surface features of the ice have been obliterated.

Omvänd skiktning (reverse layering): Layering with colder water closer to the surface. Fresh water is densest at 39 º (4 º C). At lower temperatures colder water floats on warmer water. Water cooled at the ice water interface at the bottom of an ice sheet stays there. This facilitates ice formation on the surface. Reverse layering can occur in brackish water, but not in sea water. See also språngskiktand (thermocline) and bräckvattensis (brackish ice).

Packis (pack ice): Ice consisting of jumbled, adjoining ice pieces of different ice sheets (usually in sea ice). It is often impassable with ice skates. [See photo.]

Pannkaksis (pancake ice): Ice composed  of large (several cm) ice discs, formed deep between two water layers, especially on the west coast of Sweden. It forms when a lower saline layer is colder than a less saline layer above it and the lower layer has enough dissolved salt to keep it liquid but it is cold enough to freeze the upper, less saline, layer. The ice thus formed rapidly rises to the surface and can very quickly cover large areas with thick ice. (Ed: the English term "pancake ice" refers to "tallriksis")

Pipis (pipe ice): "Candled ice", i.e., clear ice consisting of slender rod-shaped ice crystals, which are thawed by heat and sunlight. Candled ice occurs in the spring when the sun melts the grain boundaries between ice crystals. It is very unpredictable and can quickly evolve from being strong enough to hold you up to having no carrying capacity at all. Candled ice often has a dark and matte black appearance. Unless you have extensive experience with spring ice, you should not travel over candled ice. Also referred to as smalstavig is (small-rod spring ice). Also known as "thawed small-grain ice." See also våris (spring ice) and rutten is (rotten ice). [See photo 1.]  [See photo 2.]

Premiärsjö (premiere lake): A lake with an early freeze date, often very shallow, at a high-altitude and with low water flow, or, alternatively, a lake with a significant inflow of supercooled water from a river.

Regnstöp (rain slush): snow on the ice that is saturated with rain water.

Rimfrost (rime ice): Formed by humidity in the air that condenses on the ice at cold temperatures. Rimfrost creates "ice roses" or frost feathers, which are like large snowflakes. Rimfrost may make it easier to distinguish between ice of different ages, but heavy rime ice can create significant drag on skates. [See photo.]

Rulle (coil): Drafting, i.e., skating in a tight line to minimize the overall aerodynamic drag on a group of skaters. Drafting is an effective method to reduce the forces of wind, but increases the risk of a multiple swims (plurrar).

Rutten is (rotten ice): Ice in the late stage of thawing where the boundaries between ice crystals start to melt, sufficiently that the ice is permeable to water. The surface is usually dry, but water will percolate through the pores when the ice is depressed by having weight on it. This ice has very poor strength, even at considerable thickness. This ice is risky to be on. [See photo.]

Råk (rift):A large crack or fold in the ice that can be either a lead or fold down ridge, usually formed by warming temperatures. A släppråk is a wide gap between two masses of ice that drifted apart. See also uppråk (fold-up pressure ridge), nedråk (fold-down pressure ridge), skjuvråk (wide wet crack), släppråk (release crack) and havsråk (a large lead in sea ice). [See photo 1.]  [See photo 2.]

Råmning (bellowing): Loud noises like gunshots in the ice. They occur in cold weather. The sound comes from cracks forming as a result of temperature stresses in thick ice. Typically it involves no danger, but rather is a sign that the ice is thick.

Saltis (salt ice): Ice formed in salt or brackish water. Even with very low water salinity many ice properties are different than ice formed from fresh water. See also bräckvattensis (brackish ice).

Saltlake (brine): A concentrated solution of salt in water. Newly frozen saltis contains pockets of brine, which have a major effect on the properties of the ice. 

Saltsprångskikt (salt jump layer): The “halocline”, i.e., the boundary between two water masses of different salinity. The saltier water is heavier and settles at the bottom. Differences in salinity have much greater impact on water density than temperature. Water with higher salinity is always deeper, regardless of temperature. The halocline is deeper than or coincides with the thermocline layer (if both exist). Sometimes multiple layers of different salt density may occur.

Seicher (seiche): A standing wave that goes back and forth in a lake (similar to tea in a teacup when it is tipped). Caused by an air pressure change or wind. Seiches induce currents, especially in narrows, around points (headlands) and over reefs. Seiche-driven currents occur in lakes, even those with low water throughput. Sweden’s Lake Vättern has a distinct seiche with a period of three hours and a wave height of a few inches in the north and south end.

Självstöp (self-soak):  Snow that is soaked in its own meltwater, creating slush. It occurs when the snow melts during warm or sunny weather.

Sjöhävning (lake heaving): Swell. (see dyning.)

Sjösystem (lake system): Lakes linked by rivers. Lakes that are further down in a lake system often have higher water flow and are more vulnerable to strömfrätning (under-ice erosion) as a result.

Sjörök (lake smoke): Fog formed over open water in cold temperatures.  Sjörök drifting over the ice can result in substantial isrosor (ice roses or "frost flowers") of rime ice. [See photo of frost flowers.]

Skiktning (stratification): Occurs when water with different density forms stable  layers on top of each other with the least dense layer on top. Fresh water is heaviest at 4 º C. In the summer water is always stratified, with the warmest water at the top. When the lake cools to below 4 º C it becomes reverse stratified. This is normally a prerequisite for the ice to form. In salt water, conditions are more complicated as the water density also depends on salinity. See also språngskikt (thermocline) as well as saltsprångskikt (halocline).

Skjuvråk (skewed channel): An ice channel formed by tension in the ice parallel to a crack. This type of crack occurs most often parallel to a shore, especially in elongated lakes. They are typically not especially wide but they do show displacement along the crack axis.

Skredstång (glide stick): A ski on which one stands with one leg, while kicking with the other leg as is done with a kick-sled. These originated with ancient seal hunters on the Baltic Sea. An efficient means of transport over snow and soft ice. Often easier to handle than two skis. Click here to see a short video demonstrating Skredstång.

Skålgropig is (bowl-pitted ice): Wind-scalloped ice with bowl-shaped pits in the surface, often occurring in patches of dense groups. Usually formed when a hot or dry wind blows over wet ice   [See photo.]

Slukhål (drain hole): A hole in the ice where the surface water drains through the ice sheet. They grow bigger from erosion by surface water draining through holes in the ice. They often have a rounded shape and can be up to one meter in diameter. Drain holes form during a thaw when there is water on the ice. They can be difficult to detect, especially when they become covered by thin ice that is not strong enough to support a skater. Drain holes pose a great risk of injury. Not to be confused with stöphål

Släppråk (release rift):  a wide crack that is formed when two ice sheets drift apart. Leads can be formed by wind or current. They can also be formed by ice pressure in the vicinity of the ice edge or a channel. The lack of restraint along the edge of the ice may allow a crack to spread apart.  Släppråk occur most often at the end of the season, and during a thaw. In North America we would call these 'wide wet cracks' from about 3" up to a foot or two across and 'leads' if they are wider than that.  [See photo 1.]  [See photo 2.]  [See photo 3.]

Slörbogar (downwind bow): Skating with the wind at an angle from behind (often in a zigzag path). This is one way to control the buildup of speed when skating in a strong tailwind.

Smalstavig kärnis (small-rod black ice): Black ice with ice crystals that are composed of narrow vertical columns, usually formed when it is snowing lightly into the water as the ice forms. Smalstavig black ice is the ice that is the most treacherous in the spring, See smalstavig våris. Compare also with grovkristallin kärnis.

Smalstavig våris (small-rod spring ice): See pipis

Snöbrygga (snow jetty): A snow and frozen slush cap over a lead, wide wet cack in the ice. May be hazardous to cross, since the strength may be poor and difficult to assess.  See also marängis.

Snöfras (snow rustle): A thin (1/8"-1/2”) layer of moderately hard, moderately old, cold snow. It can be a tripping hazard on skates. (Ed: Often called ‘styrofoam snow’ by skaters and sailors in the US.) [See photo.]

Snöis (snow ice): Ice that is formed when snow falls in cold water. The snow may form a thick slush that can quickly freeze into a gray-white ice. The word is sometimes also used to describe slush ice. These two ice types are very similar and can be difficult to distinguish. New snow ice is often stronger than frozen slush and can be almost as strong as black ice (possibly even slightly stronger). On salt ice, snow ice often has poor strength and softens readily in warm conditions. Snow ice can have very fascinating patterns in the ice. [See photo.] (Note: The English term "snow ice" usually means stöpis (snow that falls on top of an ice layer and then is turned to slush before freezing.)

Språngskikt (jump layer). The boundary between two water masses with different density. They may be water masses of different temperature (thermocline), salinity (halocline), or chemistry (chemocline).

Strandbräcka (shore fracture): Broken ice near the shore, often on steep banks. It can be caused by ice pressure pushing pieces of the ice sheet ashore or by waves or sea level change (especially when the water rises). Strandbräcka can make it difficult to get ashore or on the ice. But a shoreline ice deposit can also give a nice skate-able path along the shore by speeding up the melting and formation of snow ice from snow-covered ice.[See photo.]

Strandkalle ([idiomatic]): beach head.

Strömfrätning (current erosion): The thinning of the ice underside by warm ground water from an underwater spring. [See photo.]  See also underfrätning (melting from the bottom) and fräthål (current hole).

Strömfåra (current line): Where water flow is greatest in a river or a lake with high throughput. Normally in the middle of the river or lake, but the current can sometimes take other routes, such as where the water is deepest. The ice in a stream cannel is often exposed to strömfrätning (under-ice current erosion)

Strömställe (current location): A place where currents are usually present.

Stöp (slush): Icy slush created from a mixture of snow and water.

Stöphål (slush hole): A hole where the water flows up through the ice sheet during slush formation. A stöphål is often seen clearly as a dark spot from which tree-like branches extend. While it is seldom dangerous, there may be a slight weakening in the middle. Also called a stöpvattenhål, it is often referred to incorrectly as a slukhål (drain hole) Called an ice octopus in North America . [See photo.]

Stöpis (slush ice): Snow transformed to slush and then frozen to ice. The slush ice consists of fine-grained ice crystals and has a gray color. Slush ice has less strength than black ice and it softens quickly at temperatures slightly above freezing. The quality can, however, vary greatly. Under the slush ice there is usually a layer of black ice. [See photo.]

Stöpisskorpa (slush ice crust): A layer of frozen slush. It is often the top layer of a three-layer sandwich with the bottom being hard (usually black) ice and the middle layer being unfrozen slush or water.

Stöpning (slushing): The process of converting snow to slush. It occurs by water being wicked up through cracks and holes in the ice (dränkstöp), from rain (regnstöp) or when the sun or warm temperatures melts the snow (självstöp). Slush becomes stöpis (snow ice) when it freezes.

Svinga (swing): When the ice moves up and down by wind-driven waves or swells rolling in from the sea. Swells or large waves can quickly break up the ice. This is particularly dangerous if it occurs when wind and swell come from different directions. Also known as ishävning.

Svingsprickor (Wave cracks): Cracks in the ice formed by waves. They are most common near the ice edge. They are usually parallel to the ice edge, and spaced about ten meters apart.. Wave cracks often have protruding edges, like tallriksis (slush-pancake ice), because the separate plates rub against each other as the waves pass underneath. It can be tiring to skate over ice with many wave cracks.

Sättis (Set-up ice): Ice made up of small frozen-together pieces that stand on end or slanting, overlapping like fish scales. Often caused by ice that has been broken up by the wind and then the pieces are pushed together and re-frozen. [See photo.]

Sötis (sweet ice): Ice formed from fresh (sweet) water.

Tallriksis (dish ice): Ice formed when slush freezes under the influence of waves. Tallriksis consists of small, fairly-round, frozen-together pieces about 0.2 to 2 meters in diameter. Before freezing together, wave action causes the free-floating "dishes" to rub against each other, developing raised edges. After the loose pieces freeze into a solid sheet, the rough edges make for unpleasant skating. (ed: In English, this type of ice is known as "pancake ice", but should not be confused with the Swedish "pannkaksis". [See photo 1.]  [See photo 2.]

Temperatursprångskikt (temperature thermocline): The boundary between two water masses with different temperatures. In the summer they prevent heating of the water under the thermocline. In large lakes the thermocline is deeper, than in more sheltered lakes. Very big lakes contain more heat relative to its surface area than smaller lakes, despite the colder surface water in summer. As a result, larger lakes take longer to cool down.

Termoklin (thermocline): The thermocline layer.

Tillflöde (feeder stream): Tributary, where water flows into a lake.

Trumis (drum ice) Ice that hangs in the air. Formed in lakes and streams with a varying water level. The word comes from the drum-like sound the ice can make when struck with something that acts as a drumstick. Also called bastrummeis (base drum ice) [See photo.]

Turbulensstråk (turbulence strings): Windblown, snow-free lanes in otherwise snow-covered ice. Usually formed by wind turbulence down wind of a lead or crack. They can provide excellent skating.

Tvångsfrusen (force-frozen): Ice that forms in a strong early-season cold spell before the lake had time to become well-cooled. The ice can quickly go out if the cold temperatures subside.

Tvåskridskois (two-skate ice): Ice that is so weak it will hold you up only if you stay straddled on two skates. If you fall through it is not strong enough to let you get back on the ice. Tvåskridskois should be stayed off of.

Tyndallsfigurer (Tyndall's Figures): Hexagonal patterns in the ice that are created when the ice thaws internally. It is often the first sign that the ice is beginning to be affected by solar radiation. It is most common in black ice with large ice crystals.  Also called Tyndallsblommor (Tyndall's flowers). [See photo.]   

Underfrätning (bottom erosion): Ice melting from the bottom. Underfrätning is usually caused by currents bringing up warmer water from the depths of the lake. [See photo.] See also strömfrätning.

Underis (under ice): The lower of two layers of ice. Occurring in wet and dry shell ice and slush with a frozen crust.

Underkylt vatten (supercooled water): Water that is chilled below the freezing point. It is a prerequisite for forming any ice but most clearly with frazil.

Uppråk, Uppvråk (up rift): An upfolded pressure ridge. The ice sheet folds upward in the center of the ridge as a result of compression in the sheet. In new ice, upfolded ridges are more common than downfolded ridges. [See photo 1.]  [See photo 2.]

Uppsaltning (up-salting): The bleeding of salt to the surface of new salt ice as it warms up or snow falls on it. The concentrated brine pockets between the ice crystals expand as they warm and they bleed to the surface. Uppsaltning creates a softer and higher drag ice surface for skating.

Uppsvallad is (up-swelled ice): Ice that freezes from water pushed or splashed onto older ice or the shore. It can provide excellent skating trails along the edge of the ice and along beaches. Also known as svallis.  [See photo.] See also landkalle

Utflöde (out flow): A lake outlet

Utmattad is (fatigued ice): Weak ice that has become fatigued by repeated stress near its breaking point. Fatigue can occur as many skaters go over thin ice. The greatest risk is in thaw conditions when the ice cannot repair the cracks by re-freezing. Fatigued ice can be tricky, since ice with many cracks does not produce the same clear sound you would expect from ice that is not fatigued. It can easily cover large areas and result in several people falling through simultaneously. It may be impossible to get back on top of theice if it is too fatigued.

Utstrålning (radiation): Infrared radiation from the ice. With a clear sky ice radiates more heat radiation than it receives from the environment. This means that the ice can grow even at several degrees above zero on a clear day, if the sun is not too strong. One condition is that the ice has a clear view of the sky. Where the sky is obscured by clouds or objects over or near the ice (trees, bridges, etc) this effect is reduced and motstrålning occurs.

Vindbrunn (wind wells): Open holes in ice new ice. Usually they are round and have diameters from a few meters to several hundred meters. The name is used even when the open water is covered by thin ice. Vindbrunn covered with thin ice are a particularly common place to fall through. Sometimes they can be very difficult to detect. There are several causes of vindbrunn: uneven cooling of the water surface, lingering currents in the water and winds that hinder new ice formation. [See photo.] (Called warm water holes on the lakeice site)

Vrakis (wreck ice): Broken ice that has frozen together in a jumbled mess (jumbled ice). It is often difficult or even impossible to skate on. [See photo.]

Vred (turned): the border between land-fast ice and moving ice (usually sea ice). Often formed by the pressure of the two sheets bearing on each other.

Vråk ([idiomatic]):pressure ridge”, i.e., a lead formed when two masses of ice press against each other so that the ice breaks or kinks. (Not a släppråk.) [See photo 1.]  [See photo 2.]

Våris (spring ice): Ice in the spring under the influence of strong sunlight. Våris can be very stable after a cold night, but it often quickly deteriorates during the day, even though it has significant thickness. The most dangerous type of våris is pipis (small grain black ice) which consists of slender rod-shaped crystals. Another very dangerous type of våris is stöpis (frozen snow slush) with an unfrozen slush/water layer between the thawed snow ice crust and the underlying ice. [See photo 1.] [See photo 2.]

Vårkrackelering (springtime crackling): When the sun penetrates the ice and melts the boundaries between ice crystals. Similar to värmekrackelering, but often more distinctly and with a dry ice surface. Subsequently,  deep furrows form between the crystals and the ice can create a cobblestone-like surface.

Vårsol (spring sun): High sun that penetrates into the ice adding heat to the ice internally. This starts being an important factor in March in the Nordic climes. Earlier in the winter, the sun is too low to have as much impact on the ice. Also, the water under the ice can begin to warm from being heated by sunlight if the ice is clear, which in turn contributes to the ice melting from below.

Värmekrackelerad (heat crackled): In a thaw, the first ice to melt is at the boundary layer between the ice crystals. The ice surface may have small grooves. The strength of the ice is quickly reduced and may be dangerous to be on. In an advanced thaw state the ice can begin to shift or make crunching noises, which is a clear warning signal. Reminiscent of vårkrackelering, but värmekrackelerad ice often has a wet surface.

Värmemängd (heat amount): The total heat capacity of the water contained in a lake. Large lakes often have a greater amount of heat content per square mile of surface than smaller lakes, even if the surface temperatures of large lakes are lower in summer. This is because the warmed water goes deeper when wind and waves stir the water more on larger surfaces. This also results in generally longer times for the large lakes to freeze. The late freeze-up means that the water has time to become well chilled, which often results in a later break-up. See also skiktning (stratification) and temperatursprångskikt (thermocline layers

Ytmjuk (soft surface): Ice with a soft surface that has higher drag when skating. [See photo.]©

Öppna (opening): An area of open water surrounded by ice, typically more than 10 meters in diameter. Could be caused by several things.

Överis (over ice): Wet shell ice i.e., a second layer of ice on top of an ice sheet, with the gap between the ice layers filled with water. Överis forms when there are puddles on the ice that skin over. Wet shell ice is treacherous. Cutting through the top layer with a skate can easily result in a fall. After tripping and falling into the top layer, the thin broken pieces can cut your hands and face. Another variant of överis is glasis, which has air instead of water is between the ice layers. [See photo 1.] 

Johan Porsby 2003 - 2007
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