Savannah morning news. [volume] (Savannah) 1868-1887, 1885-12-21
A STUDY OF COLD WAVES.
Where They Come From and How They
Travel Across the Country.


Travel Across the Country.
"Cold waveso are defined as sudden
changes from higher to lower tempera-
ture, which seem TO be independent Of the
time Of day and Of the season of the year,
and have an extended progressive move
ment across the country.
In various investigations and studies,
! Lieut.. Woodruff, Acting Signal Officer,
! says 1t has been shown that fall Of tenn
/ perature succeeds or follows an area of
! low barometer, and a rise precedes such
| an area; and that in general the reverse
| is true of an area of high barometer, viz:
that fall precedes and a rise follows it.
! In various studies upon the origin and
| movements OF areas Ofhigh and low bar
ometer, the Lieutenant says, it has been
/ shown generally that they move almost
| invariably across the United States from
west to east. The determination Of the
movement OF the area Of low barometer
largely determines the movement of the
following high. Now most of the areas Of
low barometer are formed in the region
east OF the Rocky mountains. and as these
areas move eastwardly the high moves in,
and we have accompanying cold wave
OF more or less Intensity. Even II the low
area pursue an abnormal track the clreu-
lation of the winds about the high and low
is such as TO produce almost invariably
decided fall in temperature, if the low be
eastward OF the high.
About fifteen per cent of the cold waves
come from the Pacific coast, and eighty
five per cent originate east of the Rocky
mountains, or come down the east side
OF these mountains from the British
Northwest territory. All of the cold
waves traced out during the first six
| months in each year, from 1881 to 1884, APP
peared first at Helena, Montana, except
five, which were felt at Bismarck, Dakota,
before being felt at Helena; and we must
conclude, says Lieut.. Woodruff, that they
have their origin in the vast regions of
ice and snow near the Arctic circle, far
to the north of the observing stations.
With respect to the time of day of the APP
pearance of cold waves in the Northwest.
it is found that there is no absolute rule.
and that they are quite independent of
the diurnal changes of temperature due
to the alienation of day and night.
In respect to their progressive motion,
Lieut.. W Woodruff divides cold waves into
three classes. The first class-those that
move directly across the country from
west to east, and which follow an almost
lnVarlable path along the chain of great
lakes and across New England, and do
not extend to the States south of the Ohio
| river. The second class-those which
move in 8 southeasterly direction and
cover the entire country in their progress.
And the third claes-those which move
sOutherly from Montana and Dakota to
Texas, thence through the Cult States,
and then northeasterly over the Atlantic
coast States. 1t sometimes occurs with
the third class that the cold wave is first
felt at st. Louis and Shreveport before
! being felt at st. Paul and Chicago, and
that then the cold waves takes the gene
raj movement eastward Of the second
class. The rate of progress is very vari-
able.
| In commenting upon results and in
| fluences Of cold waves, Lieut.. Woodruff
! says: alt often happens that a cold wave
/ sets IN from UheeXtreme northwest. and
/ upon reaching the Mississippi valley di-
vides, part going nOrtheRsterly to the
| lower lake region, and the other part
| southwark to the Gulf States. In either
case the intensity appears to be greatly
diminished. This action seems generally
! to be due to the sudden development of a
storm somewhere in the southern part of
the Missouri valley. Sometimes a storm
OF slight energy remains in Kansas, Mis-
souri, and Indian Territory, and has the
effect of ret8rding, or even totally de-
stroying, a cold wave. Again, when a
cold wave is retarded in this way it seems
often to gather force and intensity, and
l Tusu IdplNly lOFWaIU. ana spread over the
entire country. Another frequent feature
! is that after a cold wave commences the
| temperature continues to fall In the north
| west, and another wave is formed entirely
4 distinct from the first, from which it be-
/ comes separated by warm wave. The
warm wave is only a narrow telt, but the
cold waves are perfectly distinct.
"With respect to the prediction of the
! approach and progress Of cold waves, it is
| impossible as vet TO give set rules. One
/ great difficulty is found 10 the fact that
even after decided cold wave
IS observed in the extreme north
west, we are not able to deter
mine which one OF the three paths it
will take. A fall OF temperature of 80
deg. or 40 deg. at Bismarck or at st. Paul
does not indicate a 'nOrther' IN Texas;
neither does fall of 90 deg. or % deg. at
LeavenwOrth or st. Louis; nor does sim
liar fall at st. Paul or Chicago necessarily
bring cold wave 10 the coast. Another
great difficulty is that eight hours inter-
veDe between observations at the signal
service stations and likewise between the
report to the office at Washington"