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Freezing Drizzle
Freezing drizzle is drizzle that freezes on contact with the ground or an object at or near the surface. Its METAR code is FZDZ. Formation Although freezing drizzle and freezing rain are similar in that they both involve liquid precipitation above the surface in subfreezing temperatures and freeze on the surface, the mechanisms leading to their development are entirely different. Where freezing rain forms when frozen precipitation falls through a melting layer and turns liquid, freezing drizzle forms via the ''supercooled warm-rain process'', in which cloud droplets coalesce until they become heavy enough to fall out of the cloud, but in subfreezing conditions. Despite this process taking place in a subfreezing environment, the liquid water will not freeze if the environmental temperature is above , via supercooling. If ice crystals are already present in this environment, the liquid droplets will freeze onto these crystals and be effectively removed before they can grow large e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Drizzle
Drizzle is a light precipitation which consists of liquid water drops that are smaller than those of rain – generally smaller than in diameter. Drizzle is normally produced by low stratiform clouds and stratocumulus clouds. Precipitation rates from drizzle are on the order of a millimetre (0.04 in) per day or less at the ground. Owing to the small size of drizzle drops, under many circumstances drizzle largely evaporates before reaching the surface, and so may be undetected by observers on the ground. The METAR code for drizzle is DZ and for freezing drizzle is FZDZ. Effects While most drizzle has only a minor immediate impact upon humans, freezing drizzle can lead to treacherous conditions. Freezing drizzle occurs when supercooled drizzle drops land on a surface whose temperature is below freezing. These drops immediately freeze upon impact, leading to the buildup of sheet ice (sometimes called black ice) on the surface of roads. Occurrence Drizzle tends to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
METAR
METAR is a format for reporting weather information. A METAR weather report is predominantly used by aircraft pilots, and by meteorologists, who use aggregated METAR information to assist in weather forecasting. Raw METAR is highly standardized through the International Civil Aviation Organization (ICAO), which enables it to be understood throughout most of the world. Report names In its publication the '' Aeronautical Information Manual'' (''AIM''), the United States Federal Aviation Administration (FAA) describes the report as ''aviation routine weather report'', while the international authority for the code form, the World Meteorological Organization (WMO), describes it as the ''aerodrome routine meteorological report.'' The National Oceanic and Atmospheric Administration (part of the United States Department of Commerce) and the United Kingdom's Met Office both employ the definition used by the FAA. METAR is also known as ''Meteorological Terminal Aviation Routine Weathe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
McGraw Hill Professional
McGraw Hill is an American education science company that provides educational content, software, and services for students and educators across various levels—from K-12 to higher education and professional settings. They produce textbooks, digital learning tools, and adaptive technology to enhance learning experiences and outcomes. It is one of the "big three" educational publishers along with Houghton Mifflin Harcourt and Pearson Education. McGraw Hill also publishes reference and trade publications for the medical, business, and engineering professions. Formerly a division of The McGraw Hill Companies (later renamed McGraw Hill Financial, now S&P Global), McGraw Hill Education was divested and acquired by Apollo Global Management in March 2013 for $2.4 billion in cash. McGraw Hill was sold in 2021 to Platinum Equity for $4.5 billion. History McGraw Hill was founded in 1888, when James H. McGraw, co-founder of McGraw Hill, purchased the ''American Journal of Railway Ap ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Freezing Rain
Freezing rain is rain maintained at temperatures below melting point, freezing by the ambient air mass that causes freezing on contact with surfaces. Unlike rain and snow mixed, a mixture of rain and snow or ice pellets, freezing rain is made entirely of liquid droplets. The raindrops become supercooling, 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), glaze ice, can accumulate to a thickness of several centimeters and cover all exposed surfaces. The METAR code for freezing rain is FZRA. A storm that produces a significant thickness of glaze ice from freezing rain is often referred to as an ice storm. Although these storms are not particularly violent, freezing rain is notorious for causing travel problems on roadways, breaking tree limbs, and downing power l ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Precipitation
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, rain and snow mixed ("sleet" in Commonwealth usage), snow, ice pellets, graupel and hail. Precipitation occurs when a portion of the atmosphere becomes saturated with water vapor (reaching 100% relative humidity), 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. (Such a non-precipitating combination is a colloid.) 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 calle ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Supercooling
Supercooling, also known as undercooling, is the process of lowering the temperature of a liquid below its freezing point without it becoming a solid. Per the established international definition, supercooling means ''‘cooling a substance below the normal freezing point without solidification’.'' IIR International Dictionary of Refrigeration, http://dictionary.iifiir.org/search.php ASHRAE Terminology, https://www.ashrae.org/technical-resources/free-resources/ashrae-terminology While it can be achieved by different physical means, the postponed solidification is most often due to the absence of nucleation, seed crystals or nuclei around which a crystal structure can form. The supercooling of water can be achieved without any special techniques other than chemical demineralization, down to . Supercooled water can occur naturally, for example in the atmosphere, animals or plants. This phenomenon was first identified in 1724 by Daniel Gabriel Fahrenheit, while developing Fahren ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ice Crystals
Ice crystals are solid water (known as ice) in crystal structure, symmetrical shapes including hexagonal crystal family, hexagonal columns, hexagonal plates, and dendrite (crystal), dendritic crystals. Ice crystals are responsible for various atmospheric optics, atmospheric optical displays and cirrus cloud, cloud formations. Formation At ambient temperature and pressure, Properties of water, water molecules have a V shape. The two hydrogen atoms bond to the oxygen atom at a 105° angle. Ice crystals have a hexagonal Crystal structure, crystal lattice, meaning the water molecules arrange themselves into layered Hexagon, hexagons upon freezing. Slower crystal growth from colder and drier atmospheres produces more hexagonal symmetry. Depending on environmental temperature and humidity, ice crystals can develop from the initial hexagonal prism into many symmetric shapes. Possible shapes for ice crystals are columns, Needle ice, needles, plates and Dendrite (crystal), dendrites ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stratus Cloud
Stratus clouds are low-level clouds characterized by horizontal layering with a uniform base, as opposed to convective or cumuliform clouds formed by rising thermals. The term ''stratus'' describes flat, hazy, featureless clouds at low altitudes varying in color from dark gray to nearly white. The word ''stratus'' comes from the Latin prefix ''Strato-'', meaning "layer" or "sheet". Stratus clouds may produce a light drizzle or a small amount of snow. These clouds are essentially above-ground fog formed either through the lifting of morning fog or through cold air moving at low altitudes. Some call these clouds "high fog" for their fog-like form. Formation Stratus clouds form when weak vertical currents lift a layer of air off the ground and it depressurizes, following the lapse rate. This causes the relative humidity to increase due to the adiabatic cooling. This occurs in environments where atmospheric ''stability'' is abundant. Description Stratus clouds look like ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Glaze Ice
Glaze or glaze ice, also called glazed frost or verglas, is a smooth, transparent and homogeneous ice coating occurring when freezing rain or drizzle hits a surface. It is similar in appearance to clear ice, which forms from supercooled water droplets. It is a relatively common occurrence in temperate climates in the winter when precipitation forms in warm air aloft and falls into below-freezing temperature at the surface. Effects When the freezing rain or drizzle is light and not prolonged, the ice formed is thin. It usually causes only minor damage, relieving trees of their dead branches, etc. When large quantities accumulate, however, it is one of the most dangerous types of winter hazard. When the ice layer exceeds , tree limbs with branches heavily coated in ice can break off under the enormous weight and fall onto power lines. Windy conditions, when present, will exacerbate the damage. Power lines coated with ice become extremely heavy, causing support poles, insulators ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Black Ice
Black ice, sometimes called clear ice, is a coating of glaze ice on a surface, for example on streets or on lakes. The ice itself is not black, but visually transparent, allowing the often black road below to be seen through it and light to be transmitted. The typically low levels of noticeable ice pellets, snow, or sleet surrounding black ice means that areas of the ice are often next to invisible to drivers, cyclists or people walking on it. Thus, there is a risk of slippage and subsequent accident due to the unexpected loss of traction. Definitions The term "black ice" in the United States is defined by the National Weather Service as "patchy ice on roadways or other transportation surfaces that cannot easily be seen. It is often clear (not white) with the black road surface visible underneath. It is most prevalent during the early morning hours, especially after snowmelt on the roadways has a chance to refreeze overnight when the temperature drops below freezing. Black ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Icing Conditions
In aeronautics, icing is the atmospheric icing, formation of water ice on an aircraft. Icing has resulted in numerous aviation accidents and incidents, fatal accidents in aviation history. Ice accretion and accumulation can affect the external surfaces of an aircraft – in which case it is referred to as ''airframe icing'' – or the aircraft engine, engine, resulting in carburetor icing, air inlet icing or more generically ''engine icing''. These phenomena may possibly but do not necessarily occur together. Not all aircraft, especially general aviation aircraft, are certified for ''flight into known icing'' (FIKI) – that is flying into areas with icing conditions certain or likely to exist, based on pilot reports, METAR, observations, and Terminal Aerodrome Forecast, forecasts. In order to be FIKI-certified, aircraft must be fitted with suitable ice protection systems to prevent accidents by icing. Definition Icing conditions exist when the air contains droplets of supercoo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
American Eagle Flight 4184
American Eagle Flight 4184, officially operating as Simmons Airlines Flight 4184, was a scheduled domestic passenger flight from Indianapolis, Indiana, to Chicago, Illinois, United States. On , 1994, the performing this route flew into severe icing conditions, lost control and crashed into a field, killing all 68 people on board in the high-speed impact. Background Aircraft The aircraft involved, aircraft registration, registration was built by the French-Italian aircraft manufacturer ATR (aircraft manufacturer), ATR and was powered by two Pratt & Whitney Canada PW100, Pratt & Whitney Canada PW127 turboprops. It made its first flight on March 7, 1994, and was delivered to American Eagle on March 24, 1994. It was operated by Simmons Airlines on behalf of American Eagle (airline brand), American Eagle. American Eagle was the banner carrier regional airline branding program of AMR Corporation's regional system, prior to the formation of the fully operating certificate, cert ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
