Tornadoes 1
Transcript of Tornadoes 1
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What is Tornadoes?
Are local storms of short duration that must be
ranked high among natures most destructive
forces.
Are violent windstorms that take the form of a
rotating column of air or vortex that extends
downward from a cumulonimbus cloud.
Did you know?April is the deadliest
month for tornadoes
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A tornado is a dark funnel-shaped cloud made
up of violently rotating winds that can reachspeeds of up to 300 m.p.h.
The diameter of a tornado can vary between a
few feet and a mile, and its track can extend
from less than a mile to several hundred miles. Tornadoes generally travel in a northeast
direction (depending on the prevailing winds) at
speeds ranging from 20-60 m.p.h.
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Tornadoes Take Many Shapes and Sizes
Weak Tornadoes
69% of all tornadoes
Less than 5% of tornado
deaths
Lifetime 1-10+ minutes
Winds less than 110 mph
Violent Tornadoes
Only 2% of all tornadoes
70% of all tornado deaths
Lifetime can exceed 1 hour
Lifetime can exceed 1 hour
Strong Tornadoes
29% of all tornadoes
Nearly 30% of all tornado deaths
May last 20 minutes or longer
Winds 110-205 mph
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What Causes a Tornado?
Tornadoes are most often spawned by giant
thunderstorms known as "supercells."
These powerful, highly organized storms form when
warm, moist air along the ground rushes upward,meeting cooler, drier air.
As the rising warm air cools, the moisture it carries
condenses, forming a massive thundercloud,
sometimes growing to as much as 50,000 ft. inheight.
Variable winds at different levels of the atmosphere
feed the updraft and cause the formation of the
tornado's characteristic funnel shape.
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These warm and colt air drafts collide and twist around each other, making
the cloud become a titanic mass of turbulent air or super cell. These giant
clouds can be 20 kilometres high and as much as 32 kilometres width. On the highest top the warm air will cool and condense, forming clouds. The
cool air goes down (this is known as downdraft) where it is getting warm
again.
So in fact it is a circular course of warm moist air and cooler, drier air. These
warm and colt air drafts collide and twist around each other, making the
cloud become a titanic mass of turbulent air or super cell. These giant clouds can be 20 kilometres high and as much as 32 kilometres
width.
Super cell
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Supercell in Tornadoes
A supercell is a thunderstorm that is
characterized by the presence of a
mesocyclone; a deep, continuously-rotating
updraft.[1
Of the four classifications of thunderstorms
(supercell, squall line, multi-cell, and single-cell),
supercells are the overall least common and
have the potential to be the most severe.
Supercells are often isolated from other
thunderstorms, and can dominate the local
climate up to 32 kilometres (20 mi) away.
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Supercells are often put into two classification
types: Low-precipitation (LP) and High-
precipitation (HP). LP supercells are usually found in climates that
are more arid, such as the high plains of the
United States,
HP supercells are most often found in moist
climates.
Supercells can occur anywhere in the world
under the right pre-existing weather conditions,but they are most common in the Great Plains of
the United States.
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