Frost is a thin layer of ice on a solid surface, which forms from water vapor that deposits onto a freezing surface. Frost forms when the air contains more water vapor than it can normally hold at a specific temperature. The process is similar to the formation of dew, except it occurs below the freezing point of water typically without crossing through a liquid state.
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 by the lake water, picks up water vapor from the lake and rises through colder air. The vapor then freezes and is deposited on the leeward (downwind) shores.
A snowball is a spherical object made from snow, usually created by scooping snow with the hands and pressing the snow together to compact it into a ball. Snowballs are often used in games such as snowball fights.
A doughnut or donut is a type of pastry made from leavened fried dough. It 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. Doughnut is the traditional spelling, while donut is the simplified version; the terms are used interchangeably.
Freezing rain is 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 or ice pellets, 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.
A winter storm is an event in which wind coincides with varieties of precipitation that only occur at freezing temperatures, such as snow, mixed snow and rain, or freezing rain. In temperate continental and subarctic climates, these storms are not necessarily restricted to the winter season, but may occur in the late autumn and early spring as well. A snowstorm with strong winds and low visibility is called a blizzard.
In meteorology, precipitation is any product of the condensation of atmospheric water vapor that falls from clouds due to gravitational pull. The main forms of precipitation include drizzle, rain, sleet, snow, ice pellets, graupel and hail. Precipitation occurs when a portion of the atmosphere becomes saturated with water vapor, so that the water condenses and "precipitates" or falls. Thus, fog and mist are not precipitation; their water vapor does not condense sufficiently to precipitate, so fog and mist do not fall. Two processes, possibly acting together, can lead to air becoming saturated with water vapor: cooling the air or adding water vapor to the air. Precipitation forms as smaller droplets coalesce via collision with other rain drops or ice crystals within a cloud. Short, intense periods of rain in scattered locations are called showers.
A cruller is a deep-fried pastry popular in parts of Europe and North America. Regarded as a form of cake doughnut in the latter, it is typically either made of a string of dough that is folded over and twisted twice to create its signature shape, or formed from a rectangle of dough with a cut in the center allowing it to be pulled over and through itself to produce distinctive twists in the sides of the pastry.
In a reciprocating engine, the cylinder is the space in which a piston travels.
Thundersnow, also known as a winter thunderstorm or a thundersnow storm, is a thunderstorm in which snow falls as the primary precipitation instead of rain. It is considered a rare phenomenon. It typically falls in regions of strong upward motion within the cold sector of an extratropical cyclone. Thermodynamically, it is not different from any other type of thunderstorm, but the top of the cumulonimbus cloud is usually quite low. In addition to snow, graupel or hail may fall as well. The heavy snowfall tends to muffle the sound of the thunder so that it sounds more like a low rumble than the loud, sharp bang that is heard during regular thunderstorms.
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.
A doughnut or donut is a maneuver performed while driving a vehicle. Performing this maneuver entails rotating the rear or front of the vehicle around the opposite set of wheels in a continuous motion, creating (ideally) a circular skid-mark pattern of rubber on a carriageway and possibly even causing the tires to emit smoke from friction.
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.
A Persian, Persian roll or Pershing is a fried sweet roll or doughnut with a spiral shape similar to a cinnamon bun. It may be covered with a sugar glaze, iced or frosted, or sprinkled with sugar or cinnamon sugar.
In glassblowing, cane refers to rods of glass with color; these rods can be simple, containing a single color, or they can be complex and contain strands of one or several colors in pattern. Caneworking refers to the process of making cane, and also to the use of pieces of cane, lengthwise, in the blowing process to add intricate, often spiral, patterns and stripes to vessels or other blown glass objects. Cane is also used to make murrine, thin discs cut from the cane in cross-section that are also added to blown or hot-worked objects. A particular form of murrine glasswork is millefiori, in which many murrine with a flower-like or star-shaped cross-section are included in a blown glass piece.
Palsas are peat mounds with a permanently frozen peat and mineral soil core. They are a typical phenomenon in the polar and subpolar zone of discontinuous permafrost. One of their characteristics is having steep slopes that rise above the mire surface. This leads to the accumulation of large amounts of snow around them. The summits of the palsas are free of snow even in winter, because the wind carries the snow and deposits on the slopes and elsewhere on the flat mire surface. Palsas can be up to 150 m (490 ft) in diameter and can reach a height of 12 m (39 ft).
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 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.
This glossary of meteorology is a list of terms and concepts relevant to meteorology and atmospheric science, their sub-disciplines, and related fields.
Ice eggs, or ice balls, are a rare phenomenon caused by a process in which small pieces of sea ice in open water are rolled over by wind and currents in freezing conditions and grow into spheroid pieces of ice. They may collect into heaps of balls or 'eggs' on beaches where they pack together in striking patterns.
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