Difference between revisions of "Tornado"

From Glossary of Meteorology
imported>Liss45
imported>Liss45
Line 7: Line 7:
 
   <div class="term">
 
   <div class="term">
 
== tornado ==
 
== tornado ==
  </div>
 
  
#<div class="definition"><div class="short_definition">A violently rotating column of air, in contact with the surface, pendant from a [[cumuliform]] cloud, and often (but not always) visible as a [[funnel cloud]].</div><br/> <div class="paragraph">When tornadoes do occur without any visible funnel cloud, debris at the surface is usually the  indication of the existence of an intense [[circulation]] in contact with the ground. On a local [[scale]], the tornado is the most intense of all atmospheric circulations. Its [[vortex]], typically a few hundred  meters in diameter, usually rotates cyclonically (on rare occasions anticyclonically rotating tornadoes have been observed) with [[wind speeds]] as low as 18 m s<sup>-1</sup> (40 mph) to wind speeds as high as 135 m s<sup>-1</sup> (300 mph). Wind speeds are sometimes estimated on the basis of wind damage using the [[Fujita scale]]. Some tornadoes may also contain secondary vortices ([[suction vortices]]). Tornadoes occur on all continents but are most common in the United States, where the average number of reported tornadoes is roughly 1000 per year, with the majority of them on the central plains and in the southeastern states (<br/>''see'' [[Tornado alley]]). They can occur throughout the year at any time of day. In the central plains of the United States they are most frequent in spring during the late afternoon. <br/>''See also'' [[supercell tornado]], [[nonsupercell tornado]], [[gustnado]], [[landspout]], [[waterspout]].</div><br/> </div>
+
<div class="definition"><div class="short_definition">A rotating column of air, in contact with the surface, pendant from a [[cumuliform]] cloud, and often visible as a [[funnel cloud]] and/or circulating debris/dust at the ground.
#<div class="definition"><div class="short_definition">A violent [[thundersquall]] in West Africa and adjacent Atlantic waters.</div><br/> </div>
+
On a local [[scale]], the tornado is the most intense of all atmospheric [[circulation]]s. Its vortex usually rotates [[cyclonically]] (on rare occasions [[anticyclonically]] rotating tornadoes have been observed) with [[wind speed]]s as low as 30 m s-1 (67 mph) to as high as 135 m s-1 (300 mph), and is generally < 2 km (1.25 mi) in diameter. Tornado [[intensity]] is often estimated on the basis of wind damage using the [[Enhanced Fujita Scale]]; however, this estimate can be refined using other measurements, especially in the absence of damage indicators. Some tornadoes may also contain secondary [[vortex|vortices]] (also referred to as [[suction vortices]], subvortices, multiple, and satellite vortices).Tornadoes have been observed on all continents except Antarctica but are most common in the United States, where the average number of reported tornadoes is roughly 1000 per year, with the majority of them on the central plains and in the southeastern states (see [[tornado alley|Tornado Alley]]). They can occur throughout the year at any time of day. In the central plains of the United States they are most frequent in spring during the late afternoon.
</div>
+
 
 +
(See also [[fujita scale|Fujita Scale]].)</div><br/> </div>
 +
 
 +
''term edited 8Oct2013''
  
 
{{TermIndex}}
 
{{TermIndex}}

Revision as of 06:08, 8 October 2013



tornado

A rotating column of air, in contact with the surface, pendant from a cumuliform cloud, and often visible as a funnel cloud and/or circulating debris/dust at the ground.

On a local scale, the tornado is the most intense of all atmospheric circulations. Its vortex usually rotates cyclonically (on rare occasions anticyclonically rotating tornadoes have been observed) with wind speeds as low as 30 m s-1 (67 mph) to as high as 135 m s-1 (300 mph), and is generally < 2 km (1.25 mi) in diameter. Tornado intensity is often estimated on the basis of wind damage using the Enhanced Fujita Scale; however, this estimate can be refined using other measurements, especially in the absence of damage indicators. Some tornadoes may also contain secondary vortices (also referred to as suction vortices, subvortices, multiple, and satellite vortices).Tornadoes have been observed on all continents except Antarctica but are most common in the United States, where the average number of reported tornadoes is roughly 1000 per year, with the majority of them on the central plains and in the southeastern states (see Tornado Alley). They can occur throughout the year at any time of day. In the central plains of the United States they are most frequent in spring during the late afternoon.

(See also Fujita Scale.)

term edited 8Oct2013


Copyright 2022 American Meteorological Society (AMS). For permission to reuse any portion of this work, please contact permissions@ametsoc.org. Any use of material in this work that is determined to be “fair use” under Section 107 of the U.S. Copyright Act (17 U.S. Code § 107) or that satisfies the conditions specified in Section 108 of the U.S.Copyright Act (17 USC § 108) does not require AMS’s permission. Republication, systematic reproduction, posting in electronic form, such as on a website or in a searchable database, or other uses of this material, except as exempted by the above statement, require written permission or a license from AMS. Additional details are provided in the AMS Copyright Policy statement.