Abbeville progress. (Abbeville, Vermilion Parish, La.) 1913-1944, 1914-03-21
ALL VERY SIMPLE.
How Weather Bureau Forecasts
Storms, FroStS and Floods.
Coming of Disturbances Foretold in
5usinesslike Way Similar to
That in Which Arrival of
Shipment Is Estimated.


an idea that there is some
thing mysterious and occult about
the work of the weather bu-
reau in forecasting the coming Of
storms, frosts and floods Not few
think that the observers must neces-
sarily get their data by reading the
planets. the stars and the moon. AS a
matter OF fact the forecaster of the
bureau fOTetells the coming of disturb
ances in a businesslike way. very
similar to that in which a man who
has ordered shipment of goods
would estimate the date Of its arrival
suppose a business man has ordered
carload OF pineapples from the Ha-
waiian Islands. He would know the
average time il would take the steam
er TO make the trip to the Pacific
port. the average time for unloading
and loading into refrigerator cars, and
the average number of days to be al
lowed these cars for their trip across
the continent TO New York His esti-
mate, however. would be subject to
error because the steamship might be
delayed by fog. or the cars might meet
with an accident
storms, like pineapples, as a rule
do not originate in the United States
They come to us. some from the Phil
ippines. Japan. Siberia. Alaska. Can
ada or the Gulf of Mexico. The wealth
or bureau gets cable. telegraphic or
wireless notice of a foreign storm
Station after station, or vessel after
vessel reports the storms arrival in
its neighbOrhood. so that the general
direction and rate of progress can be
determined very early. In fact. the
arrival of some storms can be foretold
ten days in advance.
The forecasters watch for the reg
ion Of low barometer which is the
storm center around which the winds
blow. This whirl or eddy moves bod
lily forward with the general eastward
drift of about $50 miles a day in our
ATTITUDES. AS the lines Of equal pres
sure (isObars), around the low center
crowd closer together, the winds at
tending the storm increase in force
The forecaster determines the direc-
ton of movement of the storm and its
velocity
When weather disturbances are re-
ported, the forecasters know from ex-
perience about how long 1t takes them
to reach our Pacific Coast, and then
how long after they will reach the At
lantic Coast. For example, If a storm
coming from Siberia drifts eastward
around the North pole and reappears
in Alaska, it should appear in Wash
ington and Oregon in about two days:
should get to the Great Lakes in six
days and to the Atlantic Coast in
seven or eight days
Unexpected conditions may delay
storms or divert them from the
straight track just as a refrigerator
car may be thrown off it's schedule or
he shipped by accident on a wrong
road. Some of these storms deplete
themselves by running into regions of
high barometer which are of greater
magnitude and extent than the storm
itself. Some of them, however, travel
completely around the world
To keep tab on cold waves that
come into the United States from Can
ada and Alaska. the weather bureau
studies the Canadian weather reports.
England sends reports from Iceland,
the British Islands and Continental
Europe. and daily reports come from
st. Petersburg on the conditions in
Russia and Siberia.
The same businesslike system used
in tracing the track of a storm is ap-
piled in determining the arrival Of
frosts.
Flood forecasts are made in much
the same way. Information as to the
amount of rainfall at the head waters
of streams that cause floods are COW
cred by telegraphic reports sent by
local observers. AS this rain reaches
the main channel, the height of the
water in the channel is determined by
successive gauging stations. Past rec
Ords establish how much a height, say
of 20 feet at Dubuque, Iowa, will pro-
duce at Davenport. This plan is fol-
lowed all the way down the Mississip-
pi river. and at each point full allow
ance is made for the effects of water
from tributaries, and from additional
and local rainfall. AS a result of these
observations in the recent food, the
people Of Cairo had warning a week
or ten days in advance. The Pitts
/ burgh district can be given only 70
to "a hours notice, because a food is
upon thin within "a hours after a
/ heavy rain storm.