Grand Forks herald. [volume] (Grand Forks, N.D.) 1916-1955, 1921-08-18
Where Storms Breed

1t*may happen that local conditions
in a certain place will induce activity
of sufficient strength to produce
thunderstorms day after day, whereas
a nearby locality only a few miles dis
tant will develop clouds. An appro-
PIRATE name for these spots where
thundsrstorms may be bred in large
numbers is wanting. and so they are
called thunderstorm breeding spots
by a weather bureau observer, Robert
e. Horton of ~Voorheesville, N. Y, in
describing, the phenomenon. He be-
lieves such spots are numerous and
could be quite accurately and perma-
nsntly mapped with sufficient data.
For example, some cities, If not in
deed most inland cities of say 100,-
900 population or more, he says, ap-
pear to be thunderstorm spots.
Il have observed some thunder
storms yer some cities, for example,
Albany, N Y, and Providence, r. l.,
which originated Immediately over
the city and did not travel far out.
side their limits on days when there
were no other adjacent thunder.
storms" says the observer. Again,
a shallow lake with sandy margins,
situated in a forest, may serve as a
thunderstorm breeder.
The writer las observed thunder
storms originating nea the westerly
end of Oneida Lake, travelling east
ward about eighteen miles. the length
Of h lake, and then dying out soon
after reaching the easterly shore, on
days when there were no thunder
storms in the surrounding country.
Oneida Lake is about five miles wide
and eighteen miles long, located in a
flat and generally wooded region, and
has warm. shallow waters and shady
shores. The water and sand of the
lake became much warmer than the
surrounding air. especially warmer
than that in the woods on summer
afternoons.
"An observer describes a number
of occurrences of thunderstorms in
The air in the bottom of the canyon
became intensely overheated and APP
parently rose to condensation level,
which was below the rim, so that the
thunderstorm with vivid playing of
the lightning could be observed from
the top of the canyon rim, looking
over the clouds to the opposite mar
gin of the canyon which was clear.
Some western arroyos are notable
for the frequency of occurrences Of
so-called cloudburst thunderstorms.
Statistics are not available. but gen.
eral reports seem to indicate that
such storms occur more often on some
arroyos than on others adjacent to
them. The conditions Of occurrence
of thunderstorms in the Grand Can
yon and the conditions favoring thun-
derstorm breeding spots suggest that
possibly some arroyos or their drain
g areas may be 80 situated as to
form very favorable breeding spots
for thunderstorms.
THE facility of this operation may
be affected by orientation and isola-
ton, so that one arroyo basin might
be a frequent starting point for thun-
[derstorms, whereas another adjacent
to it might rarely produce them.
While this point is as vet purely hypo-
thetical, it is worthy Of further study,
since a tendency to the. frequent oc-
currence of thunderstorm in certain
arroyo basins or on their headwater
plateaus more often than on those ad-
jacent might be q very important fac
tor affecting the design Of dams such
as are commonly, located in these
lcanyonst for irrigation and other pur-
poses.
IF it is true, as the writer believes,
that certain, places az. exceedingly ia
vorable to the generation OF thunder
storms, then it appears to be a'matter
worthy OF careful study. An indica-
ton Of the truth Of the s%upposition
that cities bred -thunderstorms might
be obtained by comparison Of rain
gauges in the surrounding country
with records taken in the city during
the thunderstorm months. Records
lsof the number of thunderstorms TAX
en- in large cities are probably moi suf-
ftciently accurate to AFFORD a reliable
basis of comparison with thunder
storm frequency In the immediate
Surrounding country, Should 1t prove
true that cities are in some instances
thunderstorm breeders, whereas 9TH
or nearby cities may not possess this
Characteristic, then such facts might
have very important bearing on
various engineering problems, notably
storm-sewer design, and might yitiate
the utility OF application OF records
OF thunderstorm rain intensities In