The Leon reporter. (Leon, Iowa) 1887-1930, 1914-01-22
How the Weather Bnrcau Forecasts
Storms, FrOsts and Floods.

Office of Information, U. S. Depart
ment of Agriculture. !.
Washington, d. c., Jan. 10
Many people have the idea that there
is something mysterious and occult
about the work of the Weather Blu
reau in forecasting the coming of
storms, frosts and floods. Not a
few think that the observers must
necessarily get their data by reading
the planets, the stars and the moon.
AS matter of fact the forecaster of
the Bureau foretells the coming of
disturbances in a businesslike way,
very similar to that in which a man
who has ordered shipment of goods
, would estimate the date of it's arriv-
al. ...
| Suppose a business man had Or
: dered a carload of pineapples from
| the Hawaiian Islands. He would
know the average time it would take
| the steamer to make the trip to the
| Pacific coast port, the average time
| for unloading and loading into re-
| frigerator cars, and the average num-
| Der of days to be allowed these cars
! for their trip across the continent
! to New York. His estimate, how
ever, would be subject to error be-
| cause the steamship might be delay
ed by fog, or the cars might meet
| with an accident.
Storms, like pineapples, do not
as rule originate in the United
States. They come to us, some from
the Philippines, Japan, Siberia, Alas
ka, Canada, or the Gulf of Mexico.
The Weather Bureau gets cable,
| telegraphic or wireless notice Of a
| foreign storm. Station after station,
or vessel after vessel reports the
storms arrival in it's 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 re-
gion of low barometer which is the
storm center around which the winds
blow. This whirl or eddy moves
bodily forward with the general east
ward drift Of about $50 miles day
in our ATTITUDES. AS the lines of
equal pressure (isobars) around the
low center crowd closer together,
the winds attending the storm in
crease in force. The forecaster de-
termines the direction of movement
of the storm and it's velocity.
When weather disturbances are
reported, the forecasters know from
experience about how long it takes
them to reach our Pacific coast, and
then how long after they will reach
the Atlantic coast, for example, is
storm coming from Siberia drifts
eastward around the north pole and
reappears in Alaksa, it should appear
in Washington 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 be shipped by accident on wrong
road. Some of these storms deplete
themselves by running into regions
of high barometer which are of great
er magnitude and extent than the
storm itself. Some of them, howev
er, travel completely around the
world.
To keep tab on cold waves that
come into the United States from
Canada and Alaska, the Weather
Bureau studies the Canadian wealth
er reports England sends reports
from Iceland, the British Islands and
continental Europe, and daily reports
come from St. Petersburg on the
conditions in Russian and Siberia.
The same businesslike system us
ed in tracing the track of a storm is
applied 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 covered by Geographic reports
sent by the local observers. AS this
rain reaches the main channel, the
height of the water in the channel
is determined by successive gaging
stations. Past records establish
how much a height, say 20 feet at
Dubuque, Iowa, will produce at
Davenport, another station 80 miles
down the Mississippi. This plan is
followed all the way down the river,
and at each point full allowance is
made for the effects of water from
tributaries, and from additional and
local rainfall. AS result of these
observations in the recent flood, the
people of Cairo had warning a week
or ten days in advance. The Pitts
burgh district can be given only II
to "a hours notice, because flood
is upon them within "a hours after
a heavy rain storm.
p,rral Poet Roam Sb;nn,o,,t