STORM

Storm
An atmospheric disturbance involving perturbations of the prevailing pressure and wind fields on scales ranging from tornadoes (0.6 mi or 1 km across) to extratropical cyclones (1.2–1900 mi or 2–3000 km across); also, the associated weather (rain storm, blizzard, and the like). Storms influence human activity in such matters as agriculture, transportation, building construction, water impoundment and flood control, and the generation, transmission, and consumption of electric energy. See also Wind.
The form assumed by a storm depends on the nature of its environment, especially the large-scale flow patterns and the horizontal and vertical variation of temperature; thus the storms most characteristic of a given region vary according to latitude, physiographic features, and season. Extratropical cyclones and anticyclones are the chief disturbances over roughly half the Earth's surface. Their circulations control the embedded smaller-scale storms. Large-scale disturbances of the tropics differ fundamentally from those of extratropical latitudes. See also Hurricane; Squall; Tornado; Tropical meteorology.
Cyclones form mainly in close proximity to the jet stream, that is, in strongly baroclinic regions where there is a large increase of wind with height. Weather patterns in cyclones are highly variable, depending on moisture content and thermodynamic stability of air masses drawn into their circulations. Warm and occluded fronts, east of and extending into the cyclone center, are regions of gradual upgliding motions, with widespread cloud and precipitation but usually no pronounced concentration of stormy conditions. Extensive cloudiness also is often present in the warm sector. Passage of the cold front is marked by a sudden wind shift, often with the onset of gusty conditions, with a pronounced tendency for clearing because of general subsidence behind the front. Showers may be present in the cold air if it is moist and unstable because of heating from the surface. Thunderstorms, with accompanying squalls and heavy rain, are often set off by sudden lifting of warm, moist air at or near the cold front, and these frequently move eastward into the warm sector. See also Cyclone; Jet stream; Weather.
Extratropical cyclones alternate with high-pressure systems or anticyclones, whose circulation is generally opposite to that of the cyclone. The circulations of highs are not so intense as in well-developed cyclones, and winds are weak near their centers. In low levels the air spirals outward from a high; descent in upper levels results in warming and drying aloft. Anticyclones fall into two main categories, the warm “subtropical” and the cold “polar” highs.
Between the scales of ordinary air turbulence and of cyclones, there exist a variety of circulations over a middle-scale or mesoscale range, loosely defined as from about one-half up to a few hundred miles. Alternatively, these are sometimes referred to as subsynoptic-scale disturbances because their dimensions are so small that they elude adequate description by the ordinary synoptic network of surface weather stations.
Thus their detection often depends upon


According to the Bible, a giant storm sent by God flooded the Earth. Noah and his family and the animals entered the Ark, and "the same day were all the fountains of the great deep broken up, and the windows of heaven were opened, and the rain was upon the earth forty days and forty nights." The flood covered even the highest mountains to a depth of more than twenty feet, and all creatures died; only Noah and those with him on the Ark were left alive. See Noah's Ark for details.

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.

William Shakespeare's play The Tempest (1611) was based on the following incident.[6] Sir Thomas Gates, future governor of Virginia, was on his way to England from Jamestown, Virginia. On Saint James Day while between Cuba and the Bahamas a hurricane raged for nearly two days. Though one of the small vessels in the fleet sank to the bottom of the Florida Straits, seven of the remaining vessels reached Virginia within several days after the storm. The flagship of the fleet, known as Sea Adventure, disappeared and was presumed lost. A small bit of fortune befell the ship and her crew when they made landfall on Bermuda. The vessel was damaged on a surrounding coral reef, but all aboard survived for nearly a year on the island. The British colonists claimed the island and quickly settled Bermuda. In May 1610, they set forth for Jamestown, this time arriving at their destination.
The Ninth Wave is an 1850 painting by Ivan Aivazovsky.
The Ninth Wave is an 1850 painting by Ivan Aivazovsky.

The Romantic seascape painters J. M. W. Turner (1775-1851) and Ivan Aivazovsky (1817-1900) created some of the most lasting impressions of the sublime and stormy seas that are firmly imprinted on the popular mind. Turner's representations of powerful natural forces reinvented the traditional seascape during the first half of the nineteenth 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. A characteristic example of Turner’s dramatic seascape is The Slave Ship (properly Slavers throwing overboard the Dead and Dying - Typhoon Coming On) of 1840. Aivazovsky left several thousand turbulent canvases in which he increasingly eliminated human figures and historical background to focus on such essential elements as light, sea, and sky. His grandiose Ninth Wave



The notion that great storms accompany the passing of great persons was formerly widespread and generally accepted. The most widely mentioned instance was probably the death of Cromwell in 1658, still remembered by Samuel Pepys in his Diary four years later on 18 February 1662, while the following year he was worried by another storm: (19 Oct. 1663): Waked with a very highe winde, and said to my wife, ‘I pray God I hear not of the death of any great person, this wind is so high’, fearing that the Queene might be dead.

It could apparently be the great evil of the deceased or their great fame which caused the disturbance (Denham Tracts, 1895: ii. 29-30). On the other side of the coin, several references in Opie and Tatem (1989: 432-3) indicate that good people's deeds are often accompanied by good weather.storm, disturbance of the ordinary conditions of the atmosphere attended by wind, rain, snow, sleet, hail, or thunder and lightning. Types of storms include the extratropical cyclone, the common, large-scale storm of temperate latitudes; the tropical cyclone, or hurricane, which is somewhat smaller in area than the former and accompanied by high winds and heavy rains; the tornado, or “twister,” a small but intense storm with very high winds, usually of limited duration; and the thunderstorm, local in nature and accompanied by brief but heavy rain showers and often by hail. The term storm is also applied to blizzards, sandstorms, and dust storms, in which high wind is the dominant meteorological element. A storm surge, sometimes called a tidal wave, is a flood of ocean or lake water that occurs in areas subject to tropical storms and bordering on shallow waters, but any strong low-pressure system in a coastal area, such as a northeaster along the Atlantic coast of North America, may produce a storm surge. Storm surges are due mostly to wind, which pushes the water ahead of a storm. In Galveston, Tex., in 1900 a hurricane with a wind velocity of more than 100 mi (160 km) per hr caused an ocean storm surge 15 ft (5 m) above normal high tide levels that flooded coastal areas, resulting in the loss of thousands of lives and extensive property damage. The highest storm surge on record in the United States is that caused by Hurricane Katrina (2005), which had sustained winds at landfall in SE Louisiana of more than 140 mi (225 km) per hr and a storm surge that by one estimate reached 29 ft (8.8 m) on the SW Mississippi coast and caused coastal devastation from

Storm chasing is broadly defined as the pursuit of any severe weather condition, regardless of motive. A person who chases storms is known as a storm chaser, or simply a chaser. While witnessing a tornado is the biggest objective for many chasers, many chase thunderstorms and delight in seeing cumulonimbus structure, watching a barrage of hail and lightning, and seeing what skyscapes unfold. There are also a smaller number of storm chasers who chase hurricanes.

Storm chasing is chiefly a recreational endeavor, with motives usually given toward photographing the storm for personal reasons. Though scientific work is sometimes cited as a goal, such work is almost always impractical except for those participating in a university or government project.[1] Many chasers also are storm spotters, reporting their observations of hazardous weather to the authorities. Storm chasers are not paid to chase, with the exception of television media crews in certain television markets, video stringers and photographers, and a handful of graduate meteorologists and professors. A few entrepreneurs, however, manage to sell storm video and pictures or operate "chase tour" services. Financial returns are relatively meager given the expenses with most chasers spending more than they take in. No degree or certification is required to be a storm chaser. The NWS (National Weather Service) puts on severe weather workshops and storm spotter training.

The term "storm chaser" is also loosely applied to any of the support personnel (insurance staff, contractors, etc.) brought in to clean up after large storms.

The very first storm chaser is generally agreed to be Roger Jensen (1933–2001), a Fargo, North Dakota native who pursued western Minnesota storms from Lake Park around 1953 ([1] [2]). David Hoadley (1938– ) began chasing North Dakota storms in 1956, systematically using data from area weather offices. Bringing research chasing to the forefront was Neil Ward (1913–1972) who in the 1950s and 1960s enlisted the help of Oklahoma state police to study storms. His work pioneered modern storm spotting and made institutional chasing a reality.

In 1972 the University of Oklahoma in cooperation with the National Severe Storms Laboratory began the Tornado Intercept Project. This was the first large-scale chase activity sponsored by an institution. It culminated in a brilliant success in 1973, with the Union City, Oklahoma tornado providing a foundation for tornado morphology.[2] The project produced the first legion of veteran storm chasers, with Hoadley's Storm Track magazine bringing the community together in 1977. Storm chasing then reached popular culture in three major spurts: in 1978 with the broadcast of a segment on the television program In Search Of; in 1985 with a documentary on the PBS series Nova; and in May 1996 with the theatrical release of Twister which provided an action-packed but comically distorted glimpse at the hobby. Further early exposure to storm chasing encouraging some in the weather community resulted from several articles beginning in the late 1970s in Weatherwise magazine. Various television programs, increased coverage of severe weather by the media, and the Internet have also contributed to a significant growth of storm chasing since the mid-late 1990s. A sharp increase in the general public impulsively wandering in their local area searching for tornadoes is likewise largely attributable to these factors.

Chasing often involves driving thousands of miles in order to witness the relatively short window of time of active severe thunderstorms. It is not uncommon for a storm chaser to end up empty handed on any particular day. Storm chasers' degrees of involvement, philosophies, and techniques vary widely, but many chasers spend a significant amount of time forecasting both before going on the road as well as during the chase using a variety of sources for weather data. Most storm chasers are not meteorologists, and many chasers expend significant time and effort in learning meteorology and the intricacies of severe convective storm prediction through both study and experience.

There are inherent dangers involved in storm chasing. They range from lightning, tornadoes, large hail, flooding, hazardous road conditions (rain or hail-covered roadways), animals on the roadway, reduced visibility from heavy rain (often wind blown), and hail fog. Most directly weather-related hazards such as from a tornado are minimal, if the storm chaser is knowledgeable and cautious. Lightning, however, is an unavoidable hazard. The most significant hazard actually is driving, which, in itself, is a statistically dangerous activity that is exacerbated by the severe weather. Adding still more to this hazard are the copious distractions that can be vying for a chasers' attention: driving, communicating to chase partners and to others with a phone or radio, navigating, watching the sky, checking weather data, and shooting photos or video. Again here, caution is paramount in minimizing the risk. Chasers try to prevent the driver from multi-tasking either with chase partners covering the other aspects or the driver pulling over to do these other things if he/she is chasing alone. Many people also think that anybody can chase tornadoes, and copy the movie Twister, so they should remember that the dangers of chasing are real, and not go chasing unless experienced, or with experienced chasers. STROMS ARE SCARY!

Storm chasers are most active in May and June across the Great Plains of the United States (and Canada), with perhaps a couple hundred individuals active on any given day. Some organized chasing efforts have also begun in southeast Australia, with the biggest successes in November and December. A handful of individuals are also known to be chasing in other countries, including Israel, Italy, Spain, France, Belgium, Germany, Finland, the Netherlands, Switzerland and New Zealand; though many people trek to the Great Plains of North America from these and other countries around the world (especially the United Kingdom).
Most storm chasers will vary with regards to the amount of equipment used, some prefer a minimalist approach where only basic photographic equipment is taken on a chase while others use everything from satellite based tracking systems and live data feeds to vehicle mounted weather stations.

Top of a NSSL chase vehicle showing A/C unit, compass, and Global Positioning System.
Top of a NSSL chase vehicle showing A/C unit, compass, and Global Positioning System.

Historically, storm chasing relied on either in field analysis or now-casts from trained observers. The first in-field technology consisted of radio gear for communication. Much of this equipment could also be adapted to receive radiofax data which was useful for receiving basic observational and analysis data. The primary users of such technology were university research groups who often had larger budgets than individual chasers. Radio scanners were also heavily used to listen in on emergency services and storm spotters so as to determine where the most active or dangerous weather was located. It was not until the end of the 1980s that the evolution of the laptop computer would revolutionize storm chasing.

With the development of the mobile computers the first in computer mapping software was made available, at about the same time the VHS camcorder began to grow in popularity rapidly. Prior to the late 1980s most motion picture equipment consisted of 8mm film cameras. While the quality of the first VHS consumer cameras was quite poor when compared to traditional film formats the amount of video which could be shot with a minimal amount of resources was much greater than any film format at the time.

The 1990s marked the first technological leaps and bounds. With the quick development of solid state technology, television sets for example could be installed in most vehicles with ease allowing storm chasers to actively view local TV stations. Mobile phones became popular making group coordination easier when traditional radio communications methods were not adequate. The development of the public internet in 1993 allowed FTP access to some of the first university weather sites. The mid 1990's marked the development of smaller more efficient marine radars. While such marine radars are illegal if used in land-mobile situations many chasers were quick to adopt them in an effort to have mobile radar.[3] The first personal lightning detection and mapping devices also became available[4] and the first online radar data was also offered by private corporations often with a delay for free services. A major turning point was the advent of civilian GPS in 1996, at first GPS units were very costly and only offered basic functions but that would soon change. Towards the late 1990s the internet was awash in weather data and free weather software, the first true cellular internet modems for consumer use also emerged providing chasers access to data in the field without having to rely on a nowcaster. The NWS also released the first free, up to date Nexrad Level 3 radar data. In conjunction with all this, GPS units now had the ability to connect with computers, allowing greater ease when navigating.

2001 marked the next great technological leap for storm chasers as the first wi-fi units began to emerge offering wireless broadband service in many cases for free. In 2002, the first windows-based package to combine GPS positioning and Doppler Radar appeared called SWIFT WX[5]. SWIFT WX allowed storm chasers to accurately position themselves relative to tornadic storms while mobile. In 2004 two more storm chaser tools emerged. The first was a new XM satellite radio based system utilizing a special receiver and Baron Weather software.[6] Unlike pre-existing cellular based services there was no risk of dead spots and that meant even in the most remote areas storm chasers still had a live data feed. The second tool was a new piece of software called Grlevel3.[7] Grlevel3 utilized both free and subscripted based raw weather radar files displaying the data in a true vector format.

The most common chaser communications device is the cellular phone. Storm chasers often travel in small groups of cars, and use Citizen Band radios (declining in use) and inexpensiveGMRS/FRS hand-held transceivers (increasing in popularity) for inter-car communication. Many chasers are also amateur radio operators and sometimes use the 2 meter VHF and 70cm UHF bands to communicate between vehicles or with SKYWARN spotter networks. Scanners are often used to monitor spotter and sometimes public safety communications.

Many storm chasers have also adapted the use of laptops in conjunction with GPS receivers and laptop desks for travel directions and data collection

A increasingly common storm chaser practice is to borrow 2.4 GHz WIFI which may emanate from a commercial provider, public source or private source. Storm chasers also use high-speed internet access available in any library, even in the smallest towns in the US. Other means of live data acquisition include the use of Baron WeatherWorx ThreatNet System via XM radio's satellite (coupled with a GPS unit), or by the use of cellular internet service where one's cell phone may act as a network interface when connected to a computer system.

In-field environmental data is still popular among some storm chasers, especially temperature, humidity and wind speed data. Many have chosen to mount weather stations made by Davis Instruments Corp atop their vehicles.