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THE TORNADO HAS PROVED
THE GREATEST SINGLE THREAT TO LIFE AND PROPERTY IN OMAHA.
Each year, tornados in
the United States take an average of 115 lives and are directly responsible
for about $75 million in property damage. As a rule, however, most tornado
induced loss of life and property occurs from a very small percentage
of total tornado activity. In any given year, it is not unusual for
as much as half of all tornado property losses to be caused by less
than 5% of the reported tornados. Even more striking, during the 1960's,
85% of all tornado related deaths were attributable to only I 1/2% of
those tornados reported.
The tornado which touches
down to earth usually moves in a straight line from southwest to northeast
at about 30 to 40 m.p.h., almost always rotating in a counter-clockwise
direction. However, this relatively slow forward movement should not
be confused with its rotating wind velocity, which can range anywhere
from 80 m.p.h. to over 300 m.p.h.
In general, 80% of all
tornados occur between noon and midnight, with the largest concentration
of these striking between 4 and 6 P.M. By far, the continental plains
of North America experience more tornado activity than anywhere in the
world. In Nebraska, the season peaks in June. These statistics are caused
by climatic conditions. When cool air moves into an area occupied by
warm moist air, severe storms, and subsequently, tornados may develop.
Such conditions tend to occur in Nebraska on a late spring/early summer
afternoon.
TORNADO
STRIKES ON OMAHA
The National Weather Service
has recorded tornado strikes on Omaha for the years 1877, 1880, 1883,1913,1919,
1968 and 1975. This is
not an inordinately high
number of strikes, however, considering Omaha's proximity to areas with
extremely high figures for tornado touchdowns, and considering Nebraska's
overall tornado vulnerability statistics.
Of the tornados striking
Omaha, the 1913 Easter Sunday" tornado and the May 6, 1975 tornado
rank as major natural disasters.
On March 13, 1913, at about
6 P.M., a tornado tore through Ralston and proceeded northeast into
Omaha. Striking again at 50th and Center, it moved through the West
Farnam and Bemis Park districts and finally lifted after crossing over
Carter Lake. Almost one hundred people were killed that day. In addition,
322 people were injured, 1779 homes were destroyed or damaged, over
3000 individuals were left homeless and 3.5 million dollars in property
damage was tabulated. The tornado had wiped out an area one-quarter
mile wide and about five miles long.
Tornado Incidence by
States, 1953 to 1970: Mean Annual Tornados/10,000 square miles.
Total tornados occurring
in the United States between the years 1955 and 1967 based upon two
degree squares.
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