Winter Storm

From Wikipedia, the free encyclopedia Jump to: navigation, search “Snowstorm” redirects here. For other uses, see Snowstorm (disambiguation). A winter storm is an event in which the dominant varieties of precipitation are forms that only occur at cold temperatures, such as snow or sleet, or a rainstorm where ground temperatures are cold enough to allow ice to form (i.

e. freezing rain). In temperate continental climates, these storms are not necessarily restricted to the winter season, but may occur in the late autumn and early spring as well. Very rarely, they may form in summer, though it would have to be an abnormally cold summer, such as the summer of 1816 in the Northeast United States of America. In many locations in the Northern Hemisphere, the most powerful winter storms usually occur in March (such as the 1993 Superstorm) and, in regions where temperatures are cold enough, April.

Approaching winter storm in Salt Lake City. Snowstorms are storms where large amounts of snow fall. 

Snow is less dense than liquid water, by a factor of approximately 10 at temperatures slightly below freezing, and even more at much colder temperatures.

citation needed. Therefore, an amount of water that would produce 0. 8 in. (2 cm.

) of rain could produce at least 8 in (20 cm) of snow. Two inches of snow (5 cm. ) is enough to create serious disruptions to traffic and school transport (because of the difficulty to drive and maneuver the school buses on slick roads). This is particularly true in places where snowfall is uncommon but heavy accumulating snowfalls can happen (e. g.

, Atlanta, Seattle, London, Dublin, Canberra, Vancouver and Las Vegas). In places where snowfall is common, such as Utica, Detroit, Denver, Ottawa, Montreal, Quebec City, Chicago, Pittsburgh, Buffalo, NY, Toronto and Minneapolis, such small snowfalls are rarely disruptive, because winter tires are used, though snowfalls in excess of 6 in (15 cm) usually are. 

A massive snowstorm with strong winds and other conditions meeting certain criteria is known as a blizzard. A large number of heavy snowstorms, some of which were blizzards, occurred in the United States during 1888 and 1947 as well as the early and mid-1990s. The snowfall of 1947 exceeded two feet with drifts and snow piles from plowing that reached twelve feet and for months, temperatures did not rise high enough to melt the snow.

The 1993 “Superstorm” was manifest as a blizzard in most of the affected area. Large snowstorms could be quite dangerous: a 6 in. (15 cm. ) snowstorm will make some unplowed roads impassible, and it is possible for automobiles to get stuck in the snow. Snowstorms exceeding 12 in (30 cm) especially in southern or generally warm climates will cave the roofs of some homes and cause the loss of power.

Standing dead trees can also be brought down by the weight of the snow, especially if it is wet or very dense. 

Even a few inches of dry snow can form drifts many feet high under windy conditions. Dangers of Snow Snowstorms are usually considered less dangerous than ice storms.

However, the snow brings secondary dangers that can affect us thoroughly if we are near the place. Mountain snowstorms can produce cornices and avalanches. An additional danger, following a snowy winter, is spring flooding if the snow melts suddenly due to a dramatic rise in air temperature. Deaths can occur fr

om hypothermia, infections brought on by frostbite or car accidents due to slippery roads.

Fires and carbon monoxide poisoning can occur after a storm causes a power outage. There are also several cases of heart attacks caused by overexertion while shovelling heavy wet snow. Wintry showers or wintry mixes Many factors influence the form precipitation will take, and atmospheric temperatures are influential as well as ground conditions. Sometimes, near the rain/snow interface a region of sleet or freezing rain will occur. It is difficult to predict what form this precipitation will take, and it may alternate between rain and snow.

Therefore, weather forecasters just predict a “wintry mix”. Usually, this type of precipitation occurs at temperatures between -2 °C and 2 °C (28 °F and 36 °F). Heavy showers of freezing rain are one of the most dangerous types of winter storm. They typically occur when a layer of warm air hovers over a region, but the ambient temperature is near 0 °C (32 °F), and the ground temperature is sub-freezing. 

A storm in which only roads freeze is called a freezing rain storm; one resulting in widespread icing of plants and infrastructure is called an ice storm.

While a 10 cm (4 in) snowstorm is somewhat manageable by the standards of the northern United States and Canada, a comparable 1 cm (0. 4 in) ice storm will paralyze a region: driving becomes extremely hazardous, telephone and power lines are damaged, and crops may be ruined. Because they do not require extreme cold, ice storms often occur in warm temperature climates (such as the southern United States) and cooler ones. Ice storms in Florida will often destroy entire orange crops. Notable ice storms include an El Nino-related North American ice storm of 1998 that affected much of eastern Canada, including Montreal and Ottawa, as well as upstate New York and part of New England.

Three million people lost power, some for as long as six weeks. One-third of 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 Canadian. 

The Ice Storm of December 2002 in North Carolina resulted in massive power loss throughout much of the state, and property damage due to falling trees. Except in the mountainous western part of the state, heavy snow and icy conditions are rare in North Carolina. The Ice Storm of December 2005 was another severe winter storm producing extensive ice damage across a large portion of the Southern United States on December 14 to 16. It led to power outages and at least 7 deaths.

In January 2005 Kansas had been declared a major disaster zone by President George W. Bush after an ice storm caused nearly $39 million in damages to 32 counties. Federal funds were provided to the counties during January 4–6, 2005 to aid the recovery process. The January 2009 Central Plains and Midwest ice storm was a crippling and historic ice storm. Most places struck by the storm, saw 2 inches or more of ice accumulation, and a few of inches of snow on top it.

This brought down power lines, causing some people to go without power for a few days, to a few weeks. 

In some cases, some didn’t see power for a month or more. At the height of the storm, more than 2 million people were without power. Graupel Ice crystals fall through a cloud of super-cooled droplets-minute cloud droplets that have fallen below freezing tempature but have not frozen. The ice crystal plows into the super-cooled droplets and they immediately freeze to it.

This process forms graupel, or snow pellets, as the droplet continues to accumulate on the crystal. The pellets bounce when they hit the ground. Ice pellets Main article: Ice pellets Out ahead of the passage of a warm front, falling snow may partially melt and refreeze into a frozen rain drop before it reaches the ground. These ice pellets are called sleet. Because it is easily seen and does not accumulate ice, it is not as dangerous as freezing rain.

Rime Rime is a milky white accumulation of super-cooled cloud or fog droplets that freeze when they strike an object that has a temperature of 32 degrees F, 0 degrees C, or freezing. 

The process is called riming when super-cooled cloud droplets attach to ice crystals in the formation of graupel. Rime ice can pose a hazard to an airliner when it forms on a wing as an aircraft flies through a cloud of super-cooled droplets. 

9 Types of Snow Storms 

Snow Flurries: Flurries are defined as light snow falling for short durations.

There is little to no accumulation. The most accumulation that can be expected is a light snow dusting. 

Snow Showers: When snow is falling at varying intensities for brief periods of time, we call is snow showers. Some accumulation is possible, but not guaranteed. Snow Squalls: Often, brief but intense snow showers will be accompanied by strong, gusty winds.

These are referred to as snow squalls. Accumulation may be significant. Snow squalls are best known in the Great Lakes regions and are often referred to as Lake Effect Storms. 

Blowing Snow: Blowing snow is another winter hazard. High wind speeds can blow snow falling through the atmosphere into almost horizontal bands. In addition, lighter snows on the ground may be picked up and redistributed by the wind causing a reduction in visibility. 

Nor’easters: A low pressure storm system that is commonly attributed to the cause of winter storms although a true Nor’easter can occur any time of the year. 

Blizzards: With winds over 35 mph, blizzards are the most hazardous of the winter storms.

Visibility is often near zero and everyone is encouraged to stay in a safe and secure location during a blizzard. Driving is especially discouraged as motorists can easily be stranded. Ice Storms: One other type of dangerous winter storm condition is the ice storm. Ice storms are often to blame for multiple deaths in many regions of the world due to the loss of power experienced during an ice storm.

Ice storms can accompany any of the other types of winter precipitation. 

Sleet: Rain drops that freeze into ice pellets before reaching the ground are called sleet storms. Sleet usually bounces when hitting a surface and does not stick to objects. Accumulation can cause road conditions to become hazardous, so beware. 

Freezing Rain: When liquid precipitation comes in contact with a surface that is at or below freezing, the liquid becomes solid ice. Surfaces such as trees, cars, and roads often get a coating or glaze of ice that accumulates on the surface. Even small accumulations of ice can cause a significant hazard due to the slippery conditions. 

The weight of the solid ice on powerlines is also a significant hazard.

Sandstorms are usually found in dry desert areas, where strong winds whip up the loose top layer of sand and carry it away. Swirling, airborne sand will form a low cloud 20 inches above the ground, moving erratically as the particles collide.

Sandstorms are extremely dangerous to desert dwellers and travelers. People find it difficult to see and keep their sense of direction. Such storms also damage crops and ruin machinery. In desert areas like the Arabian peninsula, a wind known as the Simoom can carry so much sand into the air that visibility is practically reduced to zero.

Hot, electrically charged air becomes filled with tons of dust that move in thick walls or vortexes. Dust devils, small, short-lived dust vortexes that whirl along at 20 mph (3 kph), also roam across the earth. 

Sand Storm 

A sandstorm is exactly what it sounds like; a very strong windstorm, especially in the desert, that carries clouds of sand or dust, and greatly reduces visibility. These are also known as dust storms. This wind is usually caused by convection currents (which are created by intense heating of the ground), and is usually strong enough to move entire sand dunes. Air is unstable when heated, and this instability in the air will cause the ixture of higher winds in the troposphere with winds in the lower atmosphere, producing strong surface winds.

Sandstorms can interfere with travel, and sometimes obliterates entire roads, and dry, flat regions, such as parts of the western United Sates. They can be seen as solid walls of sand that are up to 5,000ft high. Similar dust storms from windborne particles can be found on the planet Mars, and are thought to be seasonal. In the United States of America, sandstorms are very rare due to the lack of large deserts, the development of proper agricultural techniques, and the common cloud cover, which will block out some of the sun’s heat.

The last recorded devastating sandstorm in American history was the Dust Bowl which caused the depression.

One that occurred near Tucson, Arizona, on July 16, 1971, was extensively documented by meteorologists. Deforestation and excessive cultivation of farmland can cause a sandstorm problem. Over-grazing and excessive use of water resources can also cause sandstorms. In order to protect themselves from sandstorms, some people wear protective goggles and suits. Special air filters can be installed in some cars to prevent sand from getting into the engine.

In Kuwait, the month of April is known as ‘sandstorm month’. Sandstorms that come from Northern Africa and drift across Europe are called ‘Sahara Sand Storms’.

Sand storms can cause hacking coughs, and the sand and dust have also been known to be capable of carrying ‘infectious diseases’. Sand particles, unlike dust ones, will clog air passages, and cause the person who breathes them in to choke. Dust particles may simply cause an allergic reaction Dust storm A dust storm or sandstorm is a meteorological phenomenon common in arid and semi-arid regions. 

Dust storms arise when a gust front blows loose sand and dust from a dry surface. Particles are transported by saltation and suspension, causing soil erosion from one place and deposition in another.

The Sahara and drylands around the Arabian peninsula are the main source of airborne dust, with some contributions from Iran, Pakistan and India into the Arabian Sea, and China’s storms deposit dust in the Pacific. It has been argued that recently, poor management of the Earth’s drylands, such as neglecting the fallow system, are increasing dust storms from desert margins nd changing both the local and global climate, and also impacting local economies. The term sandstorm is used most often in the context of desert sandstorms, especially in the Sahara, or places where sand is a more prevalent soil type than dirt or rock, when, in addition to fine particles obscuring visibility, a considerable amount of larger sand particles are blown closer to the surface. 

The term dust storm is more likely to be used when finer particles are blown long distances, especially when the dust storm affects urban areas. Causes A dust storm obscures Interstate 5 in southern California. As the force of wind passing over loosely held particles increases, particles of sand first start to vibrate, then to saltate (“leap”).

As they repeatedly strike the ground, they loosen smaller particles of dust which then begin to travel in suspension. At wind speeds above that which causes the smallest to suspend, there will be a population of dust grains moving by a range of mechanisms: suspension, saltation and creep. A recent study finds that the initial saltation of sand particles induces a static electric field by friction. Saltating sand acquires a negative charge relative to the ground which in turn loosens more sand particles which then begin saltating.

This process has been found to double the number of particles predicted by previous theories. 

Particles become loosely held mainly due to drought or arid conditions, and wind has varied causes. Gust fronts may be produced by the outflow of rain-cooled air from an intense thunderstorm, or they may represent a dry cold front, that is, a cold front that is moving into a dry air mass and is producing no precipitation. This is the type of dust storm which was common during the Dustbowl years in the U. S. Following the passage of a dry cold front, convective instability resulting from cooler air riding over heated ground can maintain the dust storm initiated at the front. 

In desert areas, dust and sand storms are most commonly caused by either thunderstorm outflows, or by strong pressure gradients which cause an increase in wind velocity over a wide area.

The vertical extent of the dust or sand that is raised is largely determined by the stability of the atmosphere above the ground as well as by the weight of the particulates. In some cases, dust and sand may be confined to a relatively shallow layer by a low-lying temperature inversion.

In other instances, dust (but not sand) may be lifted as high as 20,000 feet (6,100 m) high. Drought and wind contribute to the emergence of dust storms, as do poor farming and grazing practices by exposing the dust and sand to the wind. Dryland farming is also another cause of dust storms, since dryland farmers rely on rainfall to water their crops, they engage in practices to maintain moisture in the soil. Such practices include leaving a field fallow for a year after harvesting to allow the buildup of water to build in the soil and covering the field with dry earth in an attempt to seal in the underlying.

[citation needed] These practices make dryland agriculture susceptible to dust storms. These methods are used by farmers in eastern Washington, an arid region. 

Physical and environmental impacts 

A sandstorm can move whole sand dunes. Dust storms can carry large amounts of dust, so much so that the leading edge of one can appear as a solid wall of dust as much as 1.  km (1 mile) high. Dust and sand storms which come off the Sahara Desert are locally known as a simoom or simoon (simum, simun).

The haboob (h? bub) is a sandstorm prevalent in the region of Sudan around Khartoum; storms are very common around Khartoum every summer. When it happens you can’t see anything but a wall of sand covering your view. The Sahara desert is a key source of dust storms, particularly the Bodele Depression[4] and an area covering the confluence of Mauritania, Mali, and Algeria. Saharan dust storms have increased approximately 10-fold during the half-century since the 1950s, causing topsoil loss in Niger, Chad, northern Nigeria, and Burkina Faso. 

In Mauritania there were just two dust storms a year in the early 1960s, but there are about 80 a year today, according to Andrew Goudie, a professor of geography at Oxford University.

Levels of Saharan dust coming off the east coast of Africa in June (2007) were five times those observed in June 2006, and were the highest observed since at least 1999, which may cool Atlantic waters enough to slightly reduce hurricane activity in late 2007. Dust storms have also been shown to increase the spread of disease across the globe. Virus spores in the ground are blown into the atmosphere by the storms with the minute particles then acting like urban smog or acid rain. 

Economic impact 

Dust storms cause soil loss from the dry lands, and worse, they preferentially remove organic matter and the nutrient-rich lightest particles, thereby reducing agricultural productivity. Also the abrasive effect of the storm damages young crop plants. Other effects that may impact the economy are: reduced visibility affecting aircraft and road transportation; reduced sunlight reaching the surface; increased cloud formation increasing the heat blanket effect; high level dust sometimes obscures the sun over Florida; effects on human health of breathing dust.

Dust can also have beneficial effects where it deposits: Central and South American rain forests get most of their mineral nutrients from the Sahara; iron-poor ocean regions get iron; and dust in Hawaii increases plantain growth. 

In northern China as well as the mid-western U. S.

, ancient dust storm deposits known as loess are highly fertile soils, but they are also a significant source of contemporary dust storms when soil-securing vegetation is disturbed. MODIS Terra satellite image of the dust storm over eastern Australia taken on 23 September 2009 

• ~524BC The 50,000 strong army of Cambyses II supposedly buried by a sandstorm en route to the Siwa Oasis. 
• 1930s: A series of dust storms displaced hundreds of thousands of agricultural workers in the central United States and Canada during the Dust Bowl.
• 1934: Just one of many notable storms in the 1930s, the storm of 9-11 May 1934 began in the far north-western Great Plains and proceeded east over the northern tier of states and parts of Canada and was notable for removing the vast majority of the soil deposited since the last Ice Age over some parts of its path.
• 1935: Another major dust bowl storm took place on April 14, which became known as Black Sunday. 1954-1991: The multi-year droughts in portions of North America of 1954-56, 1976-78, and 1987-91 were noted for dust storms of the intensity seen in the middle 1930s over some fraction of their coverage and timespan, and more sporadically during the times between. 
• The three multi-year droughts were similar to the 1930s in storms being raised by synoptic scale weather events such as cyclones and cold fronts; otherwise the most common trigger is the outflow from convective activity, known as a haboob. Significant events of the latter variety occurred in Colorado and Kansas in May 2004 with winds to 100 mph, Minnesota and Wisconsin in June 2004 causing significant damage, and the upper Middle West in May 1988, notable for strong electrification and lightning activity and by one estimate reaching 30 000 ft or more.

  The first and third of this list reached black blizzard intensity, causing total blackout for some period ranging from 90 sec to 10 or more minutes, over some fraction of the ground covered. The 1987-91 drought was especially notable as in the 1930s for the large number of rain of mud events, often generated by dust in suspension and/or carried on upper-level winds.

• 1971: A dust storm that occurred near Tucson, Arizona on July 16 was extensively documented by meteorologists. 
• 1983: 1983 Melbourne dust storm: On the afternoon of February 8 a huge dust storm originating in the Mallee region of Victoria, Australia covered the city of Melbourne.
• 2007: On Saturday afternoon February 24, a large dust storm originating in the West Texas area of Amarillo covered much of the North Texas area. Strong winds caused extensive property damage to fences, roof shingles, and some buildings. The DFW Airport was severely affected, causing extensive flight delays into and out of the DFW area. Area residents suffered respiratory problems and allergic reactions, causing many people to visit hospitals.

  This event was also marked by relative humidities down to 1 per cent, in one case the juxtaposition of a c. 70°F air temp and dew point of -20°F, in and around of the area affected. 

• 2007: In June, a large dust storm generated by Cyclone Yemyin struck Karachi, Pakistan and areas of the Sindh and lower Balochistan, followed by a series of heavy rainfalls which resulted in a death toll of nearly 200. 
• 2008: On February 11, a sandstorm in the Kingdom of Bahrain in Sakhir halted Formula One testing for Ferrari, BMW and Toyota
•  2009: 2009 Australian dust storm: On September 23, a dust storm that started in South Australia and inland New South Wales, Australia, blanketed New South Wales with reddish orange skies. It stretched as far north as southern Queensland [15][16]. 
• 2010: 2010 China drought and dust storms: A sandstorm that started in Mongolia blasted Beijing on March 20, and covered large areas of China in the following days. Several countries in East Asia were affected.

  Hong Kong, Taiwan, Japan and South Korea recorded extremely poor visibility and air quality in an extremely rare level 5 hazardous rating. A number of residents reported health problems, while flights were canceled or delayed due to poor visibility caused by the sandstorm. [ w i n d s t o r m s   :   i n t r o d u c t i o n ] Dry dust whips into the air and is carried across the earth. Sand bits lodge themselves into machinery, blow under doors, beneath window cracks, into homes. Grainy pieces sting the eyes and cheeks, while winds create monstrous sand storms.

  To find out the history of dust storms and how they affect you, keep reading!

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