Storm

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A storm is any disturbed state of a planet's atmosphere, especially affecting its surface, and strongly implying severe weather. It may be marked by strong wind (a wind storm), thunder and lightning (a thunderstorm), heavy precipitation, such as ice (ice storm), or wind transporting some substance through the atmosphere (as in a dust storm, snowstorm, hailstorm, etc).

Formation

Storms are created when a center of low pressure develops, with a system of high pressure surrounding it. This combination of opposing forces can create winds and result in the formation of storm clouds, such as the cumulonimbus. Small, localized areas of low pressure can form from hot air rising off hot ground, resulting in smaller disturbances such as dust devils and whirlwinds.

Types of Storms

There are many varieties and names for storms.

• Dust devil - a small, localized updraft of rising air.
• Windstorm - a severe weather condition indicated by high winds and with little or no rain, like European windstorm.
• Squall - sudden onset of wind increase of at least 16 knots or greater sustained for at least one minute.
• Gale
• Thunderstorm

A thunderstorm is a type of storm that generates lightning and the attendant thunder. It is normally accompanied by heavy precipitation. Thunderstorms occur throughout the world, with the highest frequency in tropical rainforest regions where there are conditions of high humidity and temperature along with atmospheric instability. These storms occur when high levels of condensation form in a volume of unstable air that generates deep, rapid, upward motion in the atmosphere. The heat energy creates powerful rising air currents that swirl upwards to the tropopause. Cool descending air currents produce strong downdraughts below the storm. After the storm has spent its energy, the rising currents die away and downdraughts break up the cloud. Individual storm clouds can measure 2-10 km across.

• Tropical Cyclone

A tropical cyclone is a storm system with a closed circulation around a centre of low pressure, fueled by the heat released when moist air rises and condenses. The name underscores their origin in the tropics and their cyclonic nature. They are distinguished from other cyclonic storms such as nor'easters and polar lows by the heat mechanism that fuels them, which makes them "warm core" storm systems.

Tropical cyclones form in the oceans if the conditions in the area are favorable, and depending on their strength and location, there are various terms by which they are called, such as tropical depression, tropical storm, hurricane and typhoon.http://www.aoml.noaa.gov/hrd/tcfaq/A1.html

Tropical cyclones can produce extremely high winds, tornadoes, torrential rain (leading to mudslides and flash floods), and drive storm surge onto coastal areas. Though the effects on populations and ships can be catastrophic, tropical cyclones have been known to relieve drought conditions. They carry heat away from the tropics, an important mechanism of the global atmospheric circulation that maintains equilibrium in the environment.

• Hailstorm - a type of storm that precipitates chunks of ice that aren't snow. Hailstorms usually occur during regular thunder storms. While most of the hail that precipitates from the clouds is fairly small and virtually harmless, there have been cases of baseball and golf ball sized hail that caused much damage and injuries.

• A tornado is a violent, destructive wind storm occurring on land. Usually its appearance is that of a dark, funnel-shaped cyclone. Oftentimes tornadoes are preceded by a thunderstorm and a wall cloud. They are often called the most destructive of storms, and while they form all over the world, the American Midwest is the most prone area, especially Oklahoma and Kansas.

Storms classification

A strict meteorological definition of a terrestrial storm is a wind measuring 10 or higher on the Beaufort scale, meaning a wind speed of 89 km/h (55 mph) or more; however, popular usage is not so restrictive. Storms measuring 10 on the Beaufort scale occur once every five years on average. Storms can last anywhere from 12 to 200 hours, depending on season and geography. The east and northeast storms are noted for the most frequent repeatability and duration, especially during the cold period [link]. Big terrestrial storms alter the oceanographic conditions that in turn may affect food abundance and distribution: strong currents, strong tides, increased siltation, change in water temperatures, overturn in the water column, etc. The storm classification for assessing the relative power of northeasterly storms in the west-Atlantic has been developed by scientists at the University of Virginia. A relative frequency of 50% means here one such storm every two years and 0.1% once every 1000 years.

	Class 1 weak	Class 2 moderate	Class 3 significant	Class 4 severe	Class 5 extreme
Average peak wave height (m)	2	2.5	3.2	5	7
Average duration (h)	8	18	34	63	96
Relative frequency	49.7% (2 years)	25.2% (4 years)	22.1% (5 years)	2.4% (40 years)	0.1% (1000 years)
Beach erosion	minor	modest	across beach	severe	extreme
Dune erosion	none	minor	significant	erosion and recession	destruction
Overwash	none	none	none	severe on low-profile beaches	region-wide
Property damage	none	modest	local	community-wide	region-wide

Extraterrestrial storms

Storms are not just unique to Earth; other heavenly bodies with a sufficient atmosphere (gas giants in particular) also undergo stormy weather. A famous example is the Great Red Spot on Jupiter. Though technically a hurricane, it is larger than the earth and has been raging for at least 340 years, when it was observed by astronomer Galileo Galilei. Neptune also has its own lesser known Great Dark Spot.

In September of 1994 Hubble telescope using Wide Field Planetary Camera 2 imaged the storms on Saturn, generated by upwelling of warmer air, similar to a terrestrial thunderhead. The east-west extent of the same-year storm was equal to the diameter of Earth (ca. 7,900 miles). The storm was observed earlier in September, 1990 and acquired the name Dragon Storm.

Storm in art and culture

British painter and printmaker J. M. W. Turner (1775-1851) created some of the most lasting and famous impressions of the sublime and stormy seas. His representations of powerful natural forces reinvented the traditional seascape during the first half of the nineteeth century. Upon his travels to Holland, he took note of the familiar large rolling waves of the English seashore transforming into the sharper, choppy waves of a Dutch storm. Perhaps the best example and the most famous of Turner’s dramatic seascapes is The Slave Ship (properly Slavers throwing overboard the Dead and Dying - Typhoon Coming On) of 1840.

Russian bard Vladimir Vysotskiy has been singing the song the title of which could be roughly translated as "We say not 'storms', but 'stormes'" (Russian: "Мы говорим не 'штормы', а 'шторма'").

In Greek mythology there were several gods of storms: Briareos, by himself the god of sea storms, Aigaios, a god of the violent sea storms and Aiolos who kept the storm-winds, squalls and tempests locked away in the hollows of the floating island of Aiolia, to be released at the command of the gods.

According to the Bible, a giant storm sent by God flooded the Earth. See Noah's Ark.

See also

• Geomagnetic storm
• Extreme weather, a list of historical storms and other extreme weather
• National Oceanic and Atmospheric Administration
• Storm chasing
• Storm warning
• Tropical cyclone warnings and watches

Meterology

• Blizzard
• Hurricane
• Atmospheric pressure
• Freezing rain
• Low pressure area
• Typhoon

External links

• Branick, Michael. NOAA Technical Memorandum NWS SR-145: [A comprehensive glossary of weather terms for storm spotters.] Second edition. 1996.

 

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