Watertown weekly leader. [volume] (Watertown, Jefferson County, Wis.) 1906-1908, 1907-08-02
TELLS OF CYCLONES
THUNDER STORMS
j. L. BARTLETT. WEATHER
MAN, EXPLAINS THEM.
Addresses University Summer
StudentS-TellS What d Cyclone
is and Explains Hurricanes
Tells of Formation of TOrnddOeS
observer Weather Bru6du.

Madison, Wis, July 26-What are
cyclones, tornadoes and thunderstorms
Galveston, Pensacola, Lou sville
and many other cities have grim reason
to remember the effect, but few be-
sides the weather man know when,
where AMI how these phenomena orr
ginate, how they grow and the laws
controlling them. j. l.. Bartlett, OBJ
server for the u. S. Weather Bureau,
lectured on the subject this afternoon
to summer session students at the
University of Wisconsin, illustrating
his points with stereopticon views of
general cyclonic and anticyclonic
areas, the path and obstruction of
J the Galveston flood, the Pensacola
hurricane, and the tornadoes at Louis
vile, ST. Louis and elsewhere.
WHAT IS A CYCLONE?
"The term cyclone, scientifically
speaking, is a general one," said Mr..
Bartlett in introduction. 1t should
not be confused with tornadoes, which
is properly APPLIED only to special,
very destructive local storms. Cy-
clonic storms include the areas OF low
| barometric pressure charted daily
on the weather map, the destructive
hurricanes and typhoons of the tropics
and also tornadoes. These storms all
have the same general structure,
though they differ in al ca and strength.
The air flows spirally inward on all
sides toward center of low pressure,
where it ascends. This ascending air,
at high elevations, spreads outward
and mixes with the high upper currents
of the atmosphere. AS the air currents
move inward at the surface OF the
earth they become more and more
crowded together, and are forced to
move faster and faster. Their velocity
is also increased by the action of CEN
frugal force at the center of the storm
which forces them to move around the
center with increasing velocity, before
it ascends. Ascending air cools, it's
moisture condensing to form clouds
and rain or snow. Hence we find that
the centers of cyclonIc storms are
almost invariably accompanied by
cloudiness, rain and high winds.
HURRICANES EXPLAINED.
The low pressure area of the weather
map is usually of large extent-500
to 200 miles in diameter does
not represent destructive storm
though when its center crosses oceans
of the Great Lakes the winds may be
dangerous for small vessels. The
hurricane may be looked upon as a
concentrated low pressure area, having
diameter of perhaps 100 miles,
land causing much destruction by It's
high winds and, upon the coasts, by
the storm wave which the violent
infiowing winds heap Gp at the hurri
cane center.
HOW TORNADOS FORM.
If we still further concentrate our
low pressure area or hurricane so that
it's diameter is measured in thousands
of feet instead of in miles, we have
the tornado. In this storm we find
the typica! cyclonic spiral inflow of
wind at the earth's surface, blow
ing down trees and buildings, the
ascending current at the center of
such strength as to lift animals,
tlmbers, and even whole houses and
the out spreading currents above,
dropping at some distance away the
objects which have been carried up at
the center. The tornado cloud is
causd by condensation of moisture IN
the ascending air. as we'll as by
dust drawn up from the ground.
Tornadoes usually form in the south
east quadrant of decidedly low
pressure area, and are preceded
by very warm. moist condition of
the air. Like all cyclonic storms of
this latitude they1 move in an east
or north east direction, and their
winds are less violent on the north
side. To avoid a tornado seen ap-
preaching from the west one should
therefore run to the north or north
west: if caught suddenly by the
storm center, lie fiat upon the ground,
in a ditch or hollow, and as far as
possible from trees and movable
objects.
| Thunder storms, like tornados,
occur in the south least quadrant of
general cyclonic areas. The squall
wind which often attends them blow
straight outward from the storm
center. These squalls are some times
violent but their chief danger is in
the accompanying hail and lightning
High exposed buildings should, as a
rule, be protected by lightning rods
running down to moist earth. Metal
roofs with water-spouts running to
the ground seem to afford some pro-
lection.