See also:

• TORNADO (Span., tornada, a turning about, cf. " turn ")

TORNADO (Span., tornada, a turning about, cf. " turn ")  , a See also:

• LOCAL

local whirlwind of extreme violence, usually formed within a thunderstorm . In See also:

• APPEARANCE (from Lat. apparere, to appear)

appearance it consists of a See also:

• FUNNEL (through an O. Fr. founil, found in Breton, from Lat. infundibulum, that through which anything is poured, from fundere, to pour)

funnel-shaped See also:

• CLOUD (from the same root, if not the same word, as " clod," a word common in various forms to Teutonic languages for a mass or lump; it is first applied in the usual sense in the late 13th century; the Anglo-Saxon chid is only used in the sense of " a ma

cloud, depending from the See also:

• MASS (O.E. maesse; Fr. messe; Ger. Messe; Ital. messa; from eccl. Lat. missa)
• MASS, IN

mass of See also:

• STORM (in O. Eng..storm, and so in Du. and Low Ger.; in O. H. Ger. and mod. Ger. Sturm; the root is probably that seen in " stir," to rouse, move, disturb, cf. Ger. storen)
• STORM, THEODOR WOLDSEN (1817-1888)

storm-cloud above, and when fully See also:

• DEVELOPED

developed tapering downwards to the See also:

• EARTH
• EARTH (a word common to Teutonic languages, cf. Ger. Erde, Dutch aarde, Swed. and Dan. jord; outside Teutonic it appears only in the Gr. 'pq'e, on the ground; it has been connected by some etymologists with the Aryan root ar-, to plough, which is seen in
• EARTH, FIGURE OF
• EARTH, FIGURE OF THE

earth . Besides its whirling See also:

• MOTION (Lat. motio, from movere, to move)
• MOTION, LAWS OF

motion, a See also:

• TORNADO (Span., tornada, a turning about, cf. " turn ")

tornado has an advancing See also:

• MOVEMENT

movement of from 20 to 40 M. an See also:

• HOUR

hour—and along its own narrow path it carries destruction . Its duration is usually from See also:

• HALF

half an hour to an hour . Tornadoes are most See also:

• COMMON

common in See also:

• AMERICA

America, especially in the See also:

• MISSISSIPPI

Mississippi Valley and the See also:

• SOUTHERN

Southern states; in See also:

• EUROPE

Europe and elsewhere they are comparatively rare . Owing to their association with thunderstorms they generally occur in warm See also:

• WEATHER (O. Eng. weder; the word is common to Teutonic languages; cf. Du. weder, Dan. veir, Icel. ve8r, and Ger. Wetter and Gewitter, storm; the root is wa- to blow, from which is derived " wind ")

weather . A tornado is the result of a See also:

• CONDITION (Lat. condicio, from condicere, to agree upon, arrange; not connected with conditio, from condere, conditum, to put together)

condition of local in-stability in the See also:

• ATMOSPHERE (Gr. fir µ6r, vapour; orkaipa, a sphere)

atmosphere, originating high above the earth . A current of See also:

• AIR (from an Indo-European root meaning " breathe," " blow ")
• AIR, or ASBEN

air is induced to ascend with a rapid See also:

• SPIRAL

spiral motion See also:

• ROUND (O. Fr. rond, Lat. rotundus, the Fr. is the source also of Du. rond; Ger., Swed., Dan. and Nor. rond)

round a central core of See also:

• LOW, SETH (1850- )
• LOW, WILL HICOK (1853- )

low pressure . The moisture in the ascending air is condensed by cooling both as it ascends and as it expands into the low-pressure core . The cloud-funnel appears to grow downwards because the moisture in the air is condensed more rapidly than the air itself, following a spiral course, ascends .