Smyrna times., 1878-01-23
The Origin of Storms.
THE LAWS THAT UNDERLIE THE CHANGES OF
THE WEATHER.

THE WEATHER.
In recent essay Prof. Elias Loomis has
traced the genesis of our great storms
They generally, he finds, begin in the
neighborhood of the Rocky mountains. A
few can be traced to the Pacific ocean, near
the northern boundary of the United
States, but no example is found of any con-
derable storm arising on the Pacific coast
south of Oregon. A large proportion of
our great storms originate and are developed
wholly within our territory. The following
is the usual process in the birth of a storm;
To begin with, there is generally an area of
several hundred miles diameter, through
which the barometer stands at the mean.
On opposite sides of this area-generally
east and west, at a distance of perhaps
1000 miles apart, are areas of high barome
ter. The rise of the mercury in these side
areas is usually one quarter of an inch or
more above the mean, sometimes it is a full
inch above. The atmosphere in these two
ares begins to move toward the central
area. The currents thus established are
detected towards the right by the earth's
rotation, and a diminished pressure at the
centre; the inflow increases and comes
from all sides. The area of low pressure
assumes an oval form, but if the winds are
very violent, it may be more nearly circular
With rotation, centrifugal force is devol
oped which increases the depression. An
upward movement of the atmosphere
within the depression area is continuous
otherwise the inflow would restore the
equilibrium. This upward movement car
ries large amounts of faqueous vapor, which
when cooled at a higher level condenses a
rain. The heat liberated by condensation
increases the rarefaction Of the area anC
thus rain increases the force of a storm
though never originating it. The conclu
sion may also be deduced from the fact tha
the inflow begins before there is any pre-
cipitation of rain.
As to the forward progress of the storm
the following general observations may
made: The west wind, which is characteri!
tic of this part of the world, carries alon
the storm area. 1t may, however, meet il
terruptions, such as local storm. In tina
case the low area, thus arrested in il
forward progress, will be the seat of il
creasing force during the interruption, an
the storm for few days afterward is likel
to show greater violence. The disturbanC
which constitutes the storm if plainl
within the lower currents of the atno
phere, the upper currents being compar
lively unaffected. The pressure of tt
general wind from the west tends to fill u
the rarefed area on that side, both aboN
, and below. On the east side only IL
lower surface wind constitutes an info,
while the upper portion of the storm
moving toward the east under the pressu
of the west wind. 1t follows that the u
ward motion within the storm area tax
. place chiefly on the east side Of the are
! the motion being so rapid that the info
is sufficient to restore equilibrium.
!. further result Of this process is that tho d
preston at the center is constantly transfe
red toward the east.
: But if there should bO great precipit
: ton of vapor on the west side of the stor
| area, the center may be prevented fro
! going eastward; may be held stationar
:, or may even be quite diverted toward Il
/, west. Several remarkable instances of IL
II exceptional kind were cited. In one Of Il
II most striking of these cases-December
! 1874, to January 1S75-the storm oscillat
within a range of about 1000 miles fro
. west to east. During the most of tn
> time the winds on the west of that ar
blew with the force of hurricanes, accol
panied by snow, sleet and low tempel
ture. The explanation offered in that
, stance by Prof. Loomis is that the extensi
precipitation on the west side Of the |,
" center was probably cause of the 81,
d progress, and was itself due to a cold wi
W from over the continent, underhowinl
III warm current arising from near the G
K, Stream.