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63-574: A blizzard is a severe snowstorm characterized by strong sustained winds and low visibility, lasting for a prolonged period of time—typically at least three or four hours. A ground blizzard is a weather condition where snow that has already fallen is being blown by wind. Blizzards can have an immense size and usually stretch to hundreds or thousands of kilometres. In the United States, the National Weather Service defines

126-607: A low-pressure area whose center of rotation is just off the coast and whose leading winds in the left-forward quadrant rotate onto land from the northeast. High storm waves may sink ships at sea and cause coastal flooding and beach erosion . Notable nor'easters include The Great Blizzard of 1888 , one of the worst blizzards in U.S. history. It dropped 100–130 cm (40–50 in) of snow and had sustained winds of more than 45 miles per hour (72 km/h) that produced snowdrifts in excess of 50 feet (15 m). Railroads were shut down and people were confined to their houses for up to

189-476: A blizzard as a severe snow storm characterized by strong winds causing blowing snow that results in low visibilities. The difference between a blizzard and a snowstorm is the strength of the wind, not the amount of snow. To be a blizzard, a snow storm must have sustained winds or frequent gusts that are greater than or equal to 56 km/h (35 mph) with blowing or drifting snow which reduces visibility to 400 m or 0.25 mi or less and must last for

252-712: A cold front and warm front mix together and a blizzard forms at the border line. Another storm system occurs when a cold core low over the Hudson Bay area in Canada is displaced southward over southeastern Canada, the Great Lakes, and New England . When the rapidly moving cold front collides with warmer air coming north from the Gulf of Mexico , strong surface winds, significant cold air advection , and extensive wintry precipitation occur. Low pressure systems moving out of

315-612: A convective low acquires a well-hot circulation in the tropics it is termed a tropical cyclone . Tropical cyclones can form during any month of the year globally but can occur in either the northern or southern hemisphere during December. Atmospheric lift will also generally produce cloud cover through adiabatic cooling once the air temperature drops below the dew point as it rises, the cloudy skies typical of low-pressure areas act to dampen diurnal temperature extremes . Since clouds reflect sunlight , incoming shortwave solar radiation decreases, which causes lower temperatures during

378-413: A depth of at least 50 m (160 ft); waters of this temperature cause the overlying atmosphere to be unstable enough to sustain convection and thunderstorms. Another factor is rapid cooling with height, which allows the release of the heat of condensation that powers a tropical cyclone. High humidity is needed, especially in the lower-to-mid troposphere ; when there is a great deal of moisture in

441-460: A dusting of snow and areas such as Birmingham, Alabama , received up to 12 in (30 cm) with hurricane-force wind gusts and record low barometric pressures . Between Louisiana and Cuba, hurricane-force winds produced high storm surges across northwestern Florida, which along with scattered tornadoes killed dozens of people. In the United States, the storm was responsible for the loss of electric power to over 10 million customers. It

504-805: A layer of warm air hovers over a region, but the ambient temperature a few meters above the ground is near or below 0 °C (32 °F), and the ground temperature is sub-freezing. While a 10 cm (3.9 in) snowfall is somewhat manageable by the standards of the northern United States and Canada, a comparable 10 mm (0.39 in) precipitation of an ice storm can paralyze a region; driving becomes extremely hazardous, telephone and power lines are damaged, and crops may be ruined. Notable ice storms include an El Niño -related North American ice storm of 1998 that affected much of eastern Canada, including Montreal and Ottawa , as well as upstate New York and parts of upper New England . Three million people lost power, some for as long as six weeks. One-third of

567-636: A low of −30 °C (−22 °F), with up to 180 centimetres (71 in) of snow in the more mountainous regions, killing at least 926 people. It was the third deadliest blizzard in history. The weather also claimed more than 100,000 sheep and goats, and nearly 315,000 cattle died. The winter of 1880–1881 is widely considered the most severe winter ever known in many parts of the United States. The initial blizzard in October 1880 brought snowfalls so deep that two-story homes experienced accumulations , as opposed to drifts, up to their second-floor windows. No one

630-424: A prolonged period of time—typically three hours or more. Environment Canada defines a blizzard as a storm with wind speeds exceeding 40 km/h (25 mph) accompanied by visibility of 400 metres (0.25 mi) or less, resulting from snowfall, blowing snow, or a combination of the two. These conditions must persist for a period of at least four hours for the storm to be classified as a blizzard, except north of

693-419: A stretch of line a new storm arrived, burying it again. There were no winter thaws and on February 2, 1881, a second massive blizzard struck that lasted for nine days. In towns the streets were filled with solid drifts to the tops of the buildings and tunneling was necessary to move about. Homes and barns were completely covered, compelling farmers to construct fragile tunnels in order to feed their stock. When

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756-422: A time, particularly where snowfall is unusual or rare. A severe blizzard has winds over 72 km/h (45 mph), near zero visibility, and temperatures of −12 °C (10 °F) or lower. In Antarctica , blizzards are associated with winds spilling over the edge of the ice plateau at an average velocity of 160 km/h (99 mph). Ground blizzard refers to a weather condition where loose snow or ice on

819-462: A true whiteout, there is no visible horizon. People can become lost in their own front yards, when the door is only 3 m (10 ft) away, and they would have to feel their way back. Motorists have to stop their cars where they are, as the road is impossible to see. A nor'easter is a macro-scale storm that occurs off the New England and Atlantic Canada coastlines. It gets its name from

882-516: A vehicle's tailpipe by snow may lead to carbon monoxide buildup inside the cabin. Depending on the temperature profile in the atmosphere, snow can be either wet or dry . Dry snow, being lighter, is transported by wind more easily and accumulates more efficiently. Wet snow is heavier due to the increased water content. Significant accumulations of heavy wet snow can cause roof damage. It also requires considerably more energy to move and this can create health problems while shoveling when combined with

945-529: A week. It killed 400 people, mostly in New York . The 1972 Iran blizzard , which caused 4,000 reported deaths, was the deadliest blizzard in recorded history. Dropping as much as 26 feet (7.9 m) of snow, it completely covered 200 villages. After a snowfall lasting nearly a week, an area the size of Wisconsin was entirely buried in snow. The 2008 Afghanistan blizzard , was a fierce blizzard that struck Afghanistan on 10 January 2008. Temperatures fell to

1008-522: Is a storm that occurs in the Atlantic Ocean and northeastern Pacific Ocean , a typhoon occurs in the northwestern Pacific Ocean, and a tropical cyclone occurs in the south Pacific or Indian Ocean . Friction with land slows down the wind flowing into low-pressure systems and causes wind to flow more inward, or flowing more ageostrophically , toward their centers. Tornadoes are often too small, and of too short duration, to be influenced by

1071-558: Is an umbrella term for several different processes, all of which result in the development of some sort of cyclone . Meteorologists use the term "cyclone" where circular pressure systems flow in the direction of the Earth's rotation, which normally coincides with areas of low pressure. The largest low-pressure systems are cold-core polar cyclones and extratropical cyclones which lie on the synoptic scale . Warm-core cyclones such as tropical cyclones, mesocyclones , and polar lows lie within

1134-767: Is called lift . The moisture is collected by the wind from large bodies of water, such as a big lake or the ocean. If temperature is below freezing , 0 °C (32 °F), near the ground and up in the clouds, precipitation will fall as snow, ice, rain and snow mixed (sleet), ice pellets or even graupel (soft hail). Since cold air can not hold as much moisture as warm air, the total precipitation will be less than at higher temperature. Winter storm warnings will be issued if: Snowstorms with wind speed of more than 35 mph (16 m/s) and reduced visibility of less than 0.25 miles (400 m) for 3 hours or longer are called blizzards . Severe winter weather conditions called "winter storms", can be local weather fulfilling

1197-535: Is characterized by the development of lower air pressure over the warmest part of the various continents. The large-scale thermal lows over continents help create pressure gradients which drive monsoon circulations. In the southern hemisphere, the monsoon trough associated with the Australian monsoon reaches its most southerly latitude in February, oriented along a west-northwest/east-southeast axis. Many of

1260-416: Is initially accelerated from areas of high pressure to areas of low pressure. This is due to density (or temperature and moisture) differences between two air masses . Since stronger high-pressure systems contain cooler or drier air, the air mass is denser and flows towards areas that are warm or moist, which are in the vicinity of low-pressure areas in advance of their associated cold fronts . The stronger

1323-507: Is possible for cars to get stuck in the snow. Snow depth exceeding 12 in (30 cm) especially in southern or generally warm climates will cave the roofs of some homes and cause loss of electricity. Standing dead trees can also be brought down by the weight of the snow, especially if it is wet. Even a few inches of dry snow can form drifts many feet high under windy conditions. Accumulated snow can make driving motor vehicles very hazardous. Snow on roadways reduces friction between tires and

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1386-479: Is purported to have been directly experienced by nearly 40 percent of the country's population at that time. A total of 310 people, including 10 from Cuba, perished during this storm. The storm cost $ 6 to $ 10 billion in damages. Winter storm Winter storms are formed when moist air rises up into the atmosphere , creating low pressure near the ground and clouds up in the air. The air can also be pushed upwards by hills or large mountains. The upward motion

1449-476: Is reduced to only a few feet due to falling or blowing snow. These hazards can manifest even after snowfall has ended when strong winds are present, as these winds will pick up and transport fallen snow back onto roadways and reduce visibility in the process. This can even result in blizzard conditions if winds are strong enough. Heavy snowfall can immobilize a vehicle entirely, which may be deadly depending on how long it takes rescue crews to arrive. The clogging of

1512-437: Is typical, such small snowfalls are rarely disruptive, because of effective snow and ice removal by municipalities, increased use of four-wheel drive and snow tires , and drivers being more used to winter conditions. Snowfalls in excess of 6 in (15 cm) are usually universally disruptive. A large number of severe snowstorms, some of which were blizzards, occurred in the United States during 1888 and 1947 as well as

1575-498: The British Isles and Netherlands ), recurring low-pressure weather systems are typically known as "low levels". Cyclogenesis is the development and strengthening of cyclonic circulations, or low-pressure areas, within the atmosphere. Cyclogenesis is the opposite of cyclolysis , and has an anticyclonic (high-pressure system) equivalent which deals with the formation of high-pressure areas — anticyclogenesis . Cyclogenesis

1638-600: The Earth 's surface. Large-scale thermal lows over continents help drive monsoon circulations. Low-pressure areas can also form due to organized thunderstorm activity over warm water. When this occurs over the tropics in concert with the Intertropical Convergence Zone , it is known as a monsoon trough . Monsoon troughs reach their northerly extent in August and their southerly extent in February. When

1701-572: The Hadley cell circulation. Monsoon troughing in the western Pacific reaches its zenith in latitude during the late summer when the wintertime surface ridge in the opposite hemisphere is the strongest. It can reach as far as the 40th parallel in East Asia during August and 20th parallel in Australia during February. Its poleward progression is accelerated by the onset of the summer monsoon which

1764-753: The Southern Hemisphere shows that between the 30th and 70th parallels there are an average of 37 cyclones in existence during any 6-hour period. A separate study in the Northern Hemisphere suggests that approximately 234 significant extratropical cyclones form each winter. In Europe, particularly in the United Kingdom and in the Netherlands, recurring extratropical low-pressure weather systems are typically known as depressions. These tend to bring wet weather throughout

1827-444: The arctic tree line , where that threshold is raised to six hours. The Australia Bureau of Meteorology describes a blizzard as, "Violent and very cold wind which is laden with snow, some part, at least, of which has been raised from snow covered ground." While severe cold and large amounts of drifting snow may accompany blizzards, they are not required. Blizzards can bring whiteout conditions, and can paralyze regions for days at

1890-471: The troposphere below as air flows upwards away from the surface, which lowers surface pressures as this upward motion partially counteracts the force of gravity packing the air close to the ground. Thermal lows form due to localized heating caused by greater solar incidence over deserts and other land masses. Since localized areas of warm air are less dense than their surroundings, this warmer air rises, which lowers atmospheric pressure near that portion of

1953-460: The Gulf of Mexico. Snowstorms are storms where large quantities of snow fall. 2 in (5.1 cm) of snow is enough to create serious disruptions to traffic and school transport (because of the difficulty to drive and manoeuvre the school buses on slick roads). This is particularly true in places where snowfall is not typical but heavy accumulating snowfalls can occur. In places where snowfall

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2016-556: The North Atlantic Ocean on March 15. It is unique for its intensity, massive size and wide-reaching effect. At its height, the storm stretched from Canada towards Central America, but its main impact was on the United States and Cuba. The cyclone moved through the Gulf of Mexico, and then through the Eastern United States before moving into Canada. Areas as far south as northern Alabama and Georgia received

2079-537: The Rocky Mountains onto the Great Plains, a broad expanse of flat land, much of it covered in prairie , steppe and grassland , can cause thunderstorms and rain to the south and heavy snows and strong winds to the north. With few trees or other obstructions to reduce wind and blowing, this part of the country is particularly vulnerable to blizzards with very low temperatures and whiteout conditions. In

2142-705: The atmosphere, conditions are more favorable for disturbances to develop. Low amounts of wind shear are needed, as high shear is disruptive to the storm's circulation. Lastly, a formative tropical cyclone needs a pre-existing system of disturbed weather, although without a circulation no cyclonic development will take place. Mesocyclones form as warm core cyclones over land, and can lead to tornado formation. Waterspouts can also form from mesocyclones, but more often develop from environments of high instability and low vertical wind shear . In deserts , lack of ground and plant moisture that would normally provide evaporative cooling can lead to intense, rapid solar heating of

2205-543: The children's book The Long Winter by Laura Ingalls Wilder , in which the author tells of her family's efforts to survive. The snow arrived in October 1880 and blizzard followed blizzard throughout the winter and into March 1881, leaving many areas snowbound throughout the winter. Accurate details in Wilder's novel include the blizzards' frequency and the deep cold, the Chicago and North Western Railway stopping trains until

2268-504: The criteria for 24 hours, or large storm systems covering part of a continent for several days. With large, massive winter storms, weather in any part of the area covered by the extreme weather is usually called "storm"; even if meteorological criteria for winter storms are not met everywhere. An example of this is the February 13–17, 2021 North American winter storm with snowfall and below freezing temperatures as far south as Texas and

2331-552: The day. At night the absorptive effect of clouds on outgoing longwave radiation , such as heat energy from the surface, allows for warmer night-time minimums in all seasons. The stronger the area of low pressure, the stronger the winds experienced in its vicinity. Globally, low-pressure systems are most frequently located over the Tibetan Plateau and in the lee of the Rocky Mountains . In Europe (particularly in

2394-405: The difference between temperatures aloft and sea surface temperatures is the greatest. However, each particular basin has its own seasonal patterns. On a worldwide scale, May is the least active month while September is the most active month. Nearly one-third of the world's tropical cyclones form within the western Pacific Ocean, making it the most active tropical cyclone basin on Earth . Wind

2457-504: The direction the wind is coming from. The usage of the term in North America comes from the wind associated with many different types of storms, some of which can form in the North Atlantic Ocean and some of which form as far south as the Gulf of Mexico. The term is most often used in the coastal areas of New England and Atlantic Canada . This type of storm has characteristics similar to a hurricane . More specifically, it describes

2520-439: The early and mid-1990s. The snowfall of 1947 exceeded 2 ft (61 cm) with drifts and snow piles from plowing that reached 12 ft (3.7 m) and for months as temperatures did not rise high enough to melt the snow. The 1993 "Superstorm" manifested as a blizzard in most of the affected areas. Severe snowstorms could be quite dangerous: a 6 in (15 cm) snow depth will make some unplowed roads impassable, and it

2583-427: The first recorded use of it for weather dates to 1829, when it was defined as a "violent blow". It achieved its modern definition by 1859, when it was in use in the western United States . The term became common in the press during the harsh winter of 1880–81. In the United States, storm systems powerful enough to cause blizzards usually form when the jet stream dips far to the south, allowing cold, dry polar air from

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2646-662: The flow around Rossby waves migrate equatorward of the polar cyclones located in both the Northern and Southern hemispheres. All share one important aspect, that of upward vertical motion within the troposphere. Such upward motions decrease the mass of local atmospheric columns of air, which lowers surface pressure. Extratropical cyclones form as waves along weather fronts due to a passing by shortwave aloft or upper-level jet streak before occluding later in their life cycle as cold-core cyclones. Polar lows are small-scale, short-lived atmospheric low-pressure systems that occur over

2709-453: The ground is lifted and blown by strong winds. The primary difference between a ground blizzard as opposed to a regular blizzard is that in a ground blizzard no precipitation is produced at the time, but rather all the precipitation is already present in the form of snow or ice at the surface. The Oxford English Dictionary concludes the term blizzard is likely onomatopoeic, derived from the same sense as blow, blast, blister, and bluster ;

2772-426: The harsh weather conditions. Numerous deaths as a result of heart attacks can be attributed to snow removal. Accretion of wet snow to elevated surfaces occurs when snow is "sticky" enough which can cause extensive tree and power line damage in a manner similar to ice accretion during ice storms. Power can be lost for days during a major winter storm, and this usually means the loss of heating inside buildings. Other than

2835-545: The land cools off quickly, but the ocean keeps the heat longer due to its higher specific heat. The hot air over the ocean rises, creating a low-pressure area and a breeze from land to ocean while a large area of drying high pressure is formed over the land, increased by wintertime cooling. Monsoons resemble sea and land breezes , terms usually referring to the localized, diurnal (daily) cycle of circulation near coastlines everywhere, but they are much larger in scale - also stronger and seasonal. Large polar cyclones help determine

2898-403: The land, bringing the moist near-surface air over the oceans with it. Similar rainfall is caused by the moist ocean-air being lifted upwards by mountains , surface heating, convergence at the surface, divergence aloft, or from storm-produced outflows at the surface. However the lifting occurs, the air cools due to expansion in lower pressure, which in turn produces condensation . In winter,

2961-407: The lower layers of air. The hot air is less dense than surrounding cooler air. This, combined with the rising of the hot air, results in a low-pressure area called a thermal low . Monsoon circulations are caused by thermal lows which form over large areas of land and their strength is driven by how land heats more quickly than the surrounding nearby ocean. This generates a steady wind blowing toward

3024-698: The north to clash with warm, humid air moving up from the south. When cold, moist air from the Pacific Ocean moves eastward to the Rocky Mountains and the Great Plains , and warmer, moist air moves north from the Gulf of Mexico , all that is needed is a movement of cold polar air moving south to form potential blizzard conditions that may extend from the Texas Panhandle to the Great Lakes and Midwest . A blizzard also may be formed when

3087-423: The northern hemisphere (as the wind moves inward and is deflected right from the center of high pressure) and clockwise circulation in the southern hemisphere (as the wind moves inward and is deflected left from the center of high pressure). A tropical cyclone differs from a hurricane or typhoon based only on geographic location. A tropical cyclone is fundamentally different from a mid-latitude cyclone. A hurricane

3150-448: The northern hemisphere, and clockwise in the southern hemisphere, due to opposing Coriolis forces . Low-pressure systems form under areas of wind divergence that occur in the upper levels of the atmosphere (aloft). The formation process of a low-pressure area is known as cyclogenesis . In meteorology , atmospheric divergence aloft occurs in two kinds of places: Diverging winds aloft, ahead of these troughs, cause atmospheric lift within

3213-458: The obvious risk of hypothermia due to cold exposure, another deadly element associated with snowstorms is carbon monoxide poisoning which can happen anytime combustion products from generators or heating appliances are not properly vented. Partially or fully melted snow on roadways can refreeze when temperatures fall, creating black ice . Heavy showers of freezing rain are one of the most dangerous types of winter storm. They typically occur when

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3276-722: The ocean areas poleward of the main polar front in both the Northern and Southern Hemispheres. They are part of the larger class of mesoscale weather-systems. Polar lows can be difficult to detect using conventional weather reports and are a hazard to high-latitude operations, such as shipping and offshore platforms . They are vigorous systems that have near-surface winds of at least 17 metres per second (38 mph). Tropical cyclones form due to latent heat driven by significant thunderstorm activity, and are warm-core with well-defined circulations. Certain criteria need to be met for their formation. In most situations, water temperatures of at least 26.5 °C (79.7 °F) are needed down to

3339-414: The pressure difference, or pressure gradient , between a high-pressure system and a low-pressure system, the stronger the wind. Thus, stronger areas of low pressure are associated with stronger winds. The Coriolis force caused by the Earth 's rotation is what gives winds around low-pressure areas (such as in hurricanes , cyclones , and typhoons ) their counter-clockwise (anticlockwise) circulation in

3402-456: The road surface, which in turn lowers the maneuverability of a vehicle considerably. As a result, average driving speeds on public roads and highways are reduced by up to 40% while heavy snow is falling. Visibility is reduced by falling snow, and this is further exacerbated by strong winds which are commonly associated with winter storms producing heavy snowfall. In extreme cases , this may lead to prolonged whiteout conditions in which visibility

3465-661: The same, such as: stock up on three days of food, water, medicines and hygiene items , keep warm clothes ready, keep a flashlight and extra batteries, stay informed, help each other, do not travel unless absolutely necessary. Low pressure systems In meteorology , a low-pressure area , low area or low is a region where the atmospheric pressure is lower than that of surrounding locations. Low-pressure areas are commonly associated with inclement weather (such as cloudy, windy, with possible rain or storms), while high-pressure areas are associated with lighter winds and clear skies. Winds circle anti-clockwise around lows in

3528-399: The smaller mesoscale . Subtropical cyclones are of intermediate size. Cyclogenesis can occur at various scales, from the microscale to the synoptic scale. Larger-scale troughs, also called Rossby waves, are synoptic in scale. Shortwave troughs embedded within the flow around larger scale troughs are smaller in scale, or mesoscale in nature. Both Rossby waves and shortwaves embedded within

3591-463: The snow finally melted in late spring of 1881, huge sections of the plains experienced flooding. Massive ice jams clogged the Missouri River , and when they broke the downstream areas were inundated. Most of the town of Yankton , in what is now South Dakota, was washed away when the river overflowed its banks after the thaw. Many children—and their parents—learned of "The Snow Winter" through

3654-573: The spring thaw because the snow made the tracks impassable, the near-starvation of the townspeople, and the courage of her future husband Almanzo and another man, Cap Garland, who ventured out on the open prairie in search of a cache of wheat that no one was even sure existed. The Storm of the Century , also known as the Great Blizzard of 1993, was a large cyclonic storm that formed over the Gulf of Mexico on March 12, 1993, and dissipated in

3717-583: The steering of systems moving through the mid-latitudes, south of the Arctic and north of the Antarctic . The Arctic oscillation provides an index used to gauge the magnitude of this effect in the Northern Hemisphere. Extratropical cyclones tend to form east of climatological trough positions aloft near the east coast of continents, or west side of oceans. A study of extratropical cyclones in

3780-558: The trees in Montreal's Mount Royal park were damaged, as well as a large proportion of the sugar -producing maple trees. The amount of economic damage caused by the storm has been estimated at $ 3 billion CAD . In countries where winter storms can occur, governments and health organizations have websites and online services with advice about how to prepare for the consequences of severe weather. Advices vary with housing standards, infrastructure and safety regulations, but some tips are

3843-470: The world's rainforests are associated with these climatological low-pressure systems. Tropical cyclones generally need to form more than 555 km (345 mi) or poleward of the 5th parallel north and 5th parallel south , allowing the Coriolis effect to deflect winds blowing towards the low-pressure center and creating a circulation. Worldwide, tropical cyclone activity peaks in late summer, when

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3906-659: The year. Thermal lows also occur during the summer over continental areas across the subtropics - such as the Sonoran Desert , the Mexican Plateau , the Sahara , South America , and Southeast Asia. The lows are most commonly located over the Tibetan Plateau and in the lee of the Rocky Mountains. Elongated areas of low pressure form at the monsoon trough or Intertropical Convergence Zone as part of

3969-428: Was prepared for deep snow so early in the winter. Farmers from North Dakota to Virginia were caught flat with fields unharvested, what grain that had been harvested unmilled, and their suddenly all-important winter stocks of wood fuel only partially collected. By January train service was almost entirely suspended from the region. Railroads hired scores of men to dig out the tracks but as soon as they had finished shoveling

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