Snow roller

Last updated September 28, 2019

A snow roller is a rare meteorological phenomenon in which large snowballs are formed naturally as chunks of snow are blown along the ground by wind, picking up material along the way, in much the same way that the large snowballs used in snowmen are made. They can be as small as a tennis ball, but they can also be bigger than a car.^[1] Most snow rollers are a few inches/centimeters wide.^[2]

Snowball spherical object made from snow

A snowball is a spherical object made from snow, usually created by scooping snow with the hands, and compacting it into a roughly fist-sized ball. The snowball is often used to engage in games, such as snowball fights. Snowballs of varying size can also be used to create snowmen. Snowball fights are usually light-hearted and involve throwing snowballs at one's friends or family. The pressure exerted by the hands on the snow is a determinant for the final result. Reduced pressure leads to a light and soft snowball. Compacting humid or "packing" snow by applying a high pressure produces a harder snowball, sometimes called an ice ball, which can injure an opponent during a snowball fight.

Wind is the flow of gases on a large scale. On the surface of the Earth, wind consists of the bulk movement of air. In outer space, solar wind is the movement of gases or charged particles from the Sun through space, while planetary wind is the outgassing of light chemical elements from a planet's atmosphere into space. Winds are commonly classified by their spatial scale, their speed, the types of forces that cause them, the regions in which they occur, and their effect. The strongest observed winds on a planet in the Solar System occur on Neptune and Saturn. Winds have various aspects: velocity ; the density of the gas involved; energy content or wind energy. Wind is also an important means of transportation for seeds and small birds; with time things can travel thousands of miles in the wind.

Alternative names for snow rollers include: snow bales,^[3]snow donuts, snownuts and wind snowballs.^[2] Unlike snowballs made by people, snow rollers are typically cylindrical in shape, and are often hollow since the inner layers,^[2] which are the first layers to form, are weak and thin compared to the outer layers and can easily be blown away, leaving what looks like a doughnut or Swiss roll.

A doughnut or donut is a type of fried dough confection or dessert food. The doughnut is popular in many countries and is prepared in various forms as a sweet snack that can be homemade or purchased in bakeries, supermarkets, food stalls, and franchised specialty vendors.

A Swiss roll, jelly roll, roll cake, or cream roll is a type of sponge cake roll filled with whipped cream, jam, or icing.

The following conditions are needed for snow rollers to form:

There must be a relatively thin surface layer of wet, loose snow, with a temperature near the melting point of ice.^[2]
Under this thin layer of wet snow there must be a substrate to which the thin surface layer of wet snow will not stick, such as ice or powder snow.^[2]
The wind must be strong enough to move the snow rollers,^[2] but not strong enough to blow them apart.
Alternatively, gravity can move the snow rollers as when a snowball, such as those that will fall from a tree or cliff, lands on a steep hill and begins to roll down the hill.^[4]

The melting point of a substance is the temperature at which it changes state from solid to liquid. At the melting point the solid and liquid phase exist in equilibrium. The melting point of a substance depends on pressure and is usually specified at a standard pressure such as 1 atmosphere or 100 kPa.

Because of this last condition, snow rollers are more common in hilly areas.^[1] However, the precise nature of the conditions required makes them a very rare phenomenon.^[4]^[5]^[3]

The term snow roller also applies to a horse-drawn implement used in the mid to late 19th century (though tractor-drawn examples are still in limited use today, mainly at ski resorts) to pack snow.^{[ citation needed ]} It was mainly used in areas with high snow accumulation for access for horses and horse-drawn sleighs or wagons equipped with skis or runners. The implement was essentially, a large, very wide, wooden wheel, weighed down with stone or concrete.

Gallery

Snow roller in Krkonoše, in the Czech Republic near Poland
Snow rollers formed overnight during high winds in Venus, Pennsylvania
A snow roller in Cincinnati, Ohio, United States
Snow rollers leaving tracks in the snow
Snow rollers at Lincoln Christian College, Illinois
Snow rollers in Saxony-Anhalt, Germany

The Krkonoše, Karkonosze, Riesengebirge (German), Riesageberge or Giant Mountains, are a mountain range located in the north of the Czech Republic and the south-west of Poland, part of the Sudetes mountain system. The Czech-Polish border, which divides the historic regions of Bohemia and Silesia, runs along the main ridge. The highest peak, Sněžka, is the Czech Republic's highest point with an elevation of 1,603 metres (5,259 ft).

Poland, officially the Republic of Poland, is a country located in Central Europe. It is divided into 16 administrative subdivisions, covering an area of 312,696 square kilometres (120,733 sq mi), and has a largely temperate seasonal climate. With a population of approximately 38.5 million people, Poland is the sixth most populous member state of the European Union. Poland's capital and largest metropolis is Warsaw. Other major cities include Kraków, Łódź, Wrocław, Poznań, Gdańsk, and Szczecin.

Pennsylvania, officially the Commonwealth of Pennsylvania, is a state located in the Northeastern, Great Lakes and Mid-Atlantic regions of the United States. The Appalachian Mountains run through its middle. The Commonwealth is bordered by Delaware to the southeast, Maryland to the south, West Virginia to the southwest, Ohio to the west, Lake Erie and the Canadian province of Ontario to the northwest, New York to the north, and New Jersey to the east.

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Spinning is the twisting together of drawn-out strands of fibers to form yarn, and is a major part of the textile industry. The yarn is then used to create textiles, which are then used to make clothing and many other products. There are several industrial processes available to spin yarn, as well as hand-spinning techniques where the fiber is drawn out, twisted, and wound onto a bobbin.

Lake-effect snow is produced during cooler atmospheric conditions when a cold air mass moves across long expanses of warmer lake water. The lower layer of air, heated up by the lake water, picks up water vapor from the lake and rises up through the colder air above; the vapor then freezes and is deposited on the leeward (downwind) shores.

An avalanche is an event that occurs when a cohesive slab of snow lying upon a weaker layer of snow fractures and slides down a steep slope. Avalanches are typically triggered in a starting zone from a mechanical failure in the snowpack when the forces of the snow exceed its strength but sometimes only with gradual widening. After initiation, avalanches usually accelerate rapidly and grow in mass and volume as they entrain more snow. If the avalanche moves fast enough, some of the snow may mix with the air forming a powder snow avalanche, which is a type of gravity current.

A sled, sledge, or sleigh is a land vehicle that slides across the surface, usually of ice or snow. It is built with either a smooth underside or a separate body supported by two or more smooth, relatively narrow, longitudinal runners similar in principle to skis. This reduces the amount of friction, which helps to carry heavy loads.

Diamond dust is a ground-level cloud composed of tiny ice crystals. This meteorological phenomenon is also referred to simply as ice crystals and is reported in the METAR code as IC. Diamond dust generally forms under otherwise clear or nearly clear skies, so it is sometimes referred to as clear-sky precipitation. Diamond dust is most commonly observed in Antarctica and the Arctic, but can occur anywhere with a temperature well below freezing. In the polar regions of Earth, diamond dust may persist for several days without interruption.

Freezing rain is the name given to rain maintained at temperatures below freezing by the ambient air mass that causes freezing on contact with surfaces. Unlike a mixture of rain and snow, ice pellets, or hail, freezing rain is made entirely of liquid droplets. The raindrops become supercooled while passing through a sub-freezing layer of air hundreds of meters above the ground, and then freeze upon impact with any surface they encounter, including the ground, trees, electrical wires, aircraft, and automobiles. The resulting ice, called glaze ice, can accumulate to a thickness of several centimeters and cover all exposed surfaces. The METAR code for freezing rain is FZRA.

Goggles, or safety glasses, are forms of protective eyewear that usually enclose or protect the area surrounding the eye in order to prevent particulates, water or chemicals from striking the eyes. They are used in chemistry laboratories and in woodworking. They are often used in snow sports as well, and in swimming. Goggles are often worn when using power tools such as drills or chainsaws to prevent flying particles from damaging the eyes. Many types of goggles are available as prescription goggles for those with vision problems.

The Snowbelt is the region near the Great Lakes in North America where heavy snowfall in the form of lake-effect snow is particularly common. Snowbelts are typically found downwind of the lakes, principally off the eastern and southern shores. Lake-effect snow occurs when cold air moves over warmer water, taking up moisture that later precipitates as snow when the air moves over land and cools. The lakes produce snowsqualls and persistently cloudy skies throughout the winter, as long as air temperatures are colder than water temperatures, or until a lake freezes over.

Randy's Donuts is a bakery and landmark building in Inglewood, California, near Los Angeles International Airport, in a style that dates to a period in the early 20th century that saw a proliferation of programmatic architecture throughout Southern California. This style had its heyday from the mid-1920s to the mid-1930s. By the 1950s however, the trend of designing structures in the shape of the product sold there had changed to focus on signs rather than architecture itself. Randy's is represented by a giant doughnut on the roof of an otherwise ordinary drive-in that is a dedicated doughnut bakery. The building was designed by Henry J. Goodwin.

Ski wax is a material applied to the bottom of snow runners, including skis, snowboards, and toboggans, to improve their coefficient of friction performance under varying snow conditions. The two main types of wax used on skis are glide waxes and grip waxes. They address kinetic friction—to be minimized with a glide wax—and static friction—to be achieved with a grip wax. Both types of wax are designed to be matched with the varying properties of snow, including crystal type and size, and moisture content of the snow surface, which vary with temperature and the temperature history of the snow. Glide wax is selected to minimize sliding friction for both alpine and cross-country skiing. Grip wax provides on-snow traction for cross-country skiers, as they stride forward using classic technique.

The Morning Glory cloud is a rare meteorological phenomenon consisting of a low-level atmospheric solitary wave and associated cloud, occasionally observed in different locations around the world. The wave often occurs as an amplitude-ordered series of waves forming bands of roll clouds.

Tubing is a recreational activity where an individual rides on top of an inner tube, either on water, snow, or through the air. The tubes themselves are also known as "donuts" or "biscuits" due to their shape.

A snow cave is a shelter constructed in snow by certain animals in the wild, human mountain climbers, winter recreational enthusiasts, and winter survivalists. It has thermal properties similar to an igloo and is particularly effective at providing protection from wind as well as low temperatures. A properly made snow cave can be 0 °C or warmer inside, even when outside temperatures are −40 °C.

Architectural glass is glass that is used as a building material. It is most typically used as transparent glazing material in the building envelope, including windows in the external walls. Glass is also used for internal partitions and as an architectural feature. When used in buildings, glass is often of a safety type, which include reinforced, toughened and laminated glasses.

Sailing stones, also known as sliding rocks, walking rocks, rolling stones, and moving rocks, are a geological phenomenon where rocks move and inscribe long tracks along a smooth valley floor without human or animal intervention. The movement of the rocks occurs when large ice sheets a few millimeters thick and floating in an ephemeral winter pond start to break up during sunny days. Frozen during cold winter nights, these thin floating ice panels are driven by wind and shove rocks at speeds up to 5 meters per minute.

Classifications of snow describe and categorize the attributes of snow-generating weather events, including the individual crystals both in the air and on the ground, and the deposited snow pack as it changes over time. Snow can be classified by describing the weather event that is producing it, the shape of its ice crystals or flakes, how it collects on the ground, and thereafter how it changes form and composition. Depending on the status of the snow in the air or on the ground, a different classification applies.

A steam devil is a small, weak whirlwind over water that has drawn fog into the vortex, thus rendering it visible.

A die in polymer processing is a metal restrictor or channel capable of providing a constant cross sectional profile to a stream of liquid polymer. This allows for continuous processing of shapes such as sheets, films, pipes, rods, and other more complex profiles. This is a continuous process, allowing for constant production, as opposed to a sequential (non-constant) process such as injection molding.

References

1 2 "Snow Donut or Snow Roller a rare interesting natural phenomenon - Wireobot". Wireobot. 2016-10-27. Archived from the original on 2016-10-28. Retrieved 2016-10-27.
1 2 3 4 5 6 Zachos, Elaina (13 February 2018). "Why Snow Is Forming Donut-shape Spirals in Canada". National Geographic . Retrieved April 20, 2018.
1 2 "Rare snow rollers spotted in field near Marlborough". BBC News. 3 February 2019. Retrieved 3 February 2019.
1 2 "Snow Doughnuts Are the Real Thing". NPR.org. National Public Radio . Retrieved April 20, 2018.
↑ Holzau, Tino Bellmann @ BCS Computersysteme Holzhau. "Einzigartiges Naturschauspiel zwischen den Ortsteilen Clausnitz und Bienenmühle | Holzhau Rechenberg-Bienenmühle Clausnitz | 03.02.2019". www.holzhau.de (in German). Retrieved 2019-02-03.

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[Wireobot-1] 1 2 "Snow Donut or Snow Roller a rare interesting natural phenomenon - Wireobot". Wireobot. 2016-10-27. Archived from the original on 2016-10-28. Retrieved 2016-10-27.

[NatGeo-2] 1 2 3 4 5 6 Zachos, Elaina (13 February 2018). "Why Snow Is Forming Donut-shape Spirals in Canada". National Geographic . Retrieved April 20, 2018.

[BBC_2019-3] 1 2 "Rare snow rollers spotted in field near Marlborough". BBC News. 3 February 2019. Retrieved 3 February 2019.

[NPRradio-4] 1 2 "Snow Doughnuts Are the Real Thing". NPR.org. National Public Radio . Retrieved April 20, 2018.

[5] Holzau, Tino Bellmann @ BCS Computersysteme Holzhau. "Einzigartiges Naturschauspiel zwischen den Ortsteilen Clausnitz und Bienenmühle | Holzhau Rechenberg-Bienenmühle Clausnitz | 03.02.2019". www.holzhau.de (in German). Retrieved 2019-02-03.