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1. Understanding
a
Tornado

2. A
tornado
is
a
violently
rota/ng
column
of
air
that
is
in
contact
with
both
the
surface
of
the
earth
and
a
cumulonimbus
cloud.
They
are
o:en
referred
to
as
twisters
or
cyclones.
However,
the
word
cyclone
is
used
in
a
wider
sense
in
meteorology
for
closed
low
pressure
circula/on.
Tornadoes
come
in
many
shapes
and
sizes,
but
they
are
typically
in
the
form
of
a
visible
condensa/on
funnel,
whose
narrow
end
touches
the
earth
and
is
o:en
encircled
by
a
cloud
of
debris
and
dust.
The
most
extreme
tornadoes
can
a@ain
wind
speeds
of
more
than
300
miles
per
hour.
Tornadoes
have
been
observed
on
every
con/nent
except
Antarc/ca.
However,
the
vast
majority
of
tornadoes
occur
in
the
Tornado
Alley
region
of
the
United
States,
although
they
can
occur
nearly
anywhere
in
North
America.
They
also
occasionally
occur
in
south-­‐central
and
eastern
Asia,
northern
and
east-­‐central
South
America,
Southern
Africa,
northwestern
and
southeast
Europe,
western
and
southeastern
Australia,
and
New
Zealand.
Tornadoes
can
be
detected
before
or
as
they
occur
through
the
use
of
Pulse-­‐Doppler
radar
by
recognizing
pa@erns
in
velocity
and
reflec/vity
data,
such
as
hook
echoes
or
debris
balls,
as
well
as
by
the
efforts
of
storm
spo@ers.

3. Recently,
a
tornado,
with
peak
winds
es/mated
at
210
miles
per
hour
struck
Moore,
Oklahoma
and
adjacent
areas
killing
23
people
and
injuring
377
others.
The
tornado
was
part
of
a
larger
weather
system
that
had
produced
several
other
tornadoes
over
the
previous
two
days.
Despite
the
tornado
following
a
roughly
similar
track
to
the
even
deadlier
1999
Bridge
Creek–Moore
tornado,
very
few
homes
and
neither
of
the
stricken
schools
had
purpose-­‐built
storm
shelters.
Though
tornadoes
can
strike
in
an
instant,
there
are
precau/ons
and
preventa/ve
measures
that
people
can
take
to
increase
the
chances
of
surviving
a
tornado.
Authori/es
such
as
the
Storm
Predic/on
Center
advise
having
a
pre-­‐determined
plan
should
a
tornado
warning
be
issued.
When
a
warning
is
issued,
going
to
a
basement
or
an
interior
first-­‐floor
room
of
a
sturdy
building
greatly
increases
chances
of
survival.
In
tornado-­‐prone
areas,
many
buildings
have
storm
cellars
on
the
property.
These
underground
refuges
have
saved
thousands
of
lives.

4. Some
countries
have
meteorological
agencies
which
distribute
tornado
forecasts
and
increase
levels
of
alert
of
a
possible
tornado,
such
as
tornado
watches
and
warnings
in
the
United
States
and
Canada.
Weather
radios
provide
an
alarm
when
a
severe
weather
advisory
is
issued
for
the
local
area,
though
these
are
mainly
available
only
in
the
United
States.
Unless
the
tornado
is
far
away
and
highly
visible,
meteorologists
advise
that
drivers
park
their
vehicles
far
to
the
side
of
the
road
and
find
a
sturdy
shelter.
If
no
sturdy
shelter
is
nearby,
geng
low
in
a
ditch
is
the
next
best
op/on.
Highway
overpasses
are
one
of
the
worst
places
to
take
shelter
during
tornadoes,
as
the
constricted
space
can
be
subject
to
increased
wind
speed
and
funneling
of
debris
underneath
the
overpass.