Rock Island Argus. (Rock Island, Ill.) 1893-1920, 1905-07-14

snow a tall IN temperature OF D 10 20
degrees within a few minutes. AS the
storm passes, the barometer falls
Slightly before beginning a gradual
rise. and the wind dies down TO an or
i binary velocity.
! In the vicinity of the tri-cities, Rock
Island, Davenport and Moline, thunder
storms are most numerous during
May. June and July, the records at
the local Office of the L. s. weather
bureau showing seven storms, on the
average. in each of these months. Most
of the summer rainfall occurs in the
short. heavy downpOurs that accom-
pany thunderstOrms.- and it not unfre-
quently happens that the amount of
rain precipitated in a single storm. or
! a series of storms. exceeds the average
, for the entire month. Thus, at Daven-
port. while the normal for June is
inches. greater amounts of rain have
| been recorded within "a hours twice in
| the history of the local office The new
! 24-hour record for June is 500 inches,
made during the storm that began at
10 D. IN On the 9Th of the month just
past This is 0.12 inch less than the
24-hour record for July, SIS inches hav-
ing been recorded on July 10 and IA,
| 1889 II is difficult to comprehend the
| real significance of such an enormous
volume Of water. AS l inchaof rain per
acre makes 22.G24 gallons, equal to
| 226.Gl3 pounds. or more than 113 tons
of 1000 pounds each. some idea may
| be reached as to what these figures
really mean. About two-thirds of the
Col h. rfnf,, -,
| tri-cities. amounting here 10 nearly SO
inches. falls during the six months
| from April TO September. inclusive, and
the average wettest period for the en-
| tire year covers the first nine days of
June
Color Is Guide.
The coloring of the clouds and the
degree Of agitation visible among them
are good guides TO the intensity a storm
is likely to exhibit Thunderstorms
and tornadoes occur under much the
same conditions. but the latter should
be recognized by the peculiar ominous
appearance of the clouds and by the
characteristic funnel that is suspended
from the cloud mass.
Thunderstorms are secondary dis
turbances. usually found in the south
east quadrant of the area of low pres
sure. of storm center. outlined on the
weather map. They may occur in
well defined belt that has a progress
i've motion towards the east. or they
may be purely local in character.
! Numerous instances of the latter class
can be recalled by any one who has
resided long in Davenport. Rock ISL
and or Moline. in which d copious rain
| fell in one of these cities and none
| whatever occurred in either of the
other two.
Frequent claims are made by the res
| idents of this immediate section that
the course of severe thunderstorms is
| influenced by the local topography 1t
may possibly be true that purely local
storms are influenced by the relative
positions of the Rock river and Missis-
sippi river valley. and their lines of
bluffs. though it has not been demon
strated but it is not thought that these
typographical features would affect the
direction of the larger storms that
move eastward at such elevations that
their course can not be perceptibly al
tered by considerable hills, or even by
low mountains. The apparent dividing
of a storm is probably in many cases
the result of the observers inability
TO Judge its course correctly in the
first place.
Ideal Conditions.
When an area of low pressure ex-
tends from southwest to northeast
across the middle Missouri valley
northwestern Iowa and southeastern
South Dakota. almost ideal conditions
exist for the formation of thunder
storms in the vicinity of the tri-cities
and the intensity of the storms will
| depend largely upon the departure
| from the normal of the barometer
readings near a storm center. These
are the conditions that prevailed on
the morning of June 9. of the present
year on which date. ana the following
day. the record breaking rains and
several electrical storms now so well
remembered, occurred in this locality.
! On that morning the center of the area
of low pressure extended from eastern
Colorado northeastward to Minnesota,
with the lowest barometer readings.
1906 inches. at Huron. S. D., and Sioux
| City, Iowa On the morning of the
| 10th rainfalls of more than 4.40 inches
were recorded al LeClaire. Davenport
and Keokuk. Heavy rains did not eX-
tend above Dubuque nor to any great
distance below the southern line of
| Iowa
1t is desired again to call attention
TO the so-called forecasts that are foist-
/ ed upon the public by INSCRIPTIONS
| persons who issue their guesses sew
eral months. or a year ahead. These
predictions. (which are the work of
| charlatans actuated solely by motives
of personal gain, are without any sci
entific basis and the sensational ian
guage in which they are couched.
should, therefore, occasion no alarm.
Many of the best papers decline 10