Evening star., 1936-06-09

What has happened in two months to
change the Southwest's dust bowl into
a mud puddle and the Southeast into
a brick kiln?
Normally Amarillo. Tex, a dust bowl
town. has an average of 2i2 inches OF
rain in May. For the past two years
it has had much less. This year 1t hao
inches.
Meanwhile. towns like Columbia, S. c.,
and Charlotte. N. c., has less than
one-tenth of an inch Of precipitation,
whereas normally they should have mad
about 2 inches.
The trouble is, explains j. c. Kincer,
chief of the division of climatology Of
the United States Weather Bureau, that
the highs and lows have struck out on
new paths across the continent-for the
past month at least.
The highs are waves of cold air coming
In from the Arctic basin east OF the
Rocky Mountains. The lows are waves
of warm. moist air coming from the Gulf
of Mexico, or forming in the PACING
Northwest or the extreme Southwest.
When a low comes in contact with
high it tries to climb over 1t just as If 1t
were a mountain-that is, according to
well-known physical principles, warm
air rises. AS it rises it is cooled and this
has the effect of squeezing water
out of it, just as If 1t were a soaked
sponge.
Now generally, in order to get rain,
a low must be just south OF locality
and q high just north of it, SO that the
spreading air waves meet just over it.
The two centers may be hundreds Of
miles apart, but the same relationship
holds The relative position of the
high and the low must be such that the
high is sucking in most warm air from
the south.
During the past two years the centers
of the lows have been passing almost
directly over the dust bowl and the
centers of the highs have been far to
the northward-over Southern Canada.
The two fronts" met above halfway
between over the corn belt and there
was rain. The great area southwark
from Kansas City suffered its worst
drought.
Late in April of this year the whole
picture changed. Both highs and lows
shifted to the southwark. The lows
were just far enough to the south to
deluge q good part Of the dust bowl.
On the other hand the extreme north
west-North Dakota and Montana
have been north or in the center of the
highs so that they appear to be enter
ing a great drought.
The same phenomenon has been work.
ing in the East. Ordinarily the lows pass
far to the southwark over the Appa-
lachians so that the Southeast gets
good supply of rain. This year they are
cutting sharply to the northeast. passing
out over New York and New England,
so that the cotton States are well to
the south of them. The result is the
developing drought, broken in the past
few days by Spotty rains.
There is no way of telling, Mr.. Kincer
says. how long this condition will con-
tinue. Ordinarily when the high and
lows start moving in certain general
pathways they build up tendency to
continue. They are like men beating
paths. On the other hand they may
shift suddenly and radically. When the
weather changes the change is apt to
be a complete reversal.
This, Mr.. Kincer points out, Is well
illustrated by the present situation In
the Southeast Here the great floods OF
March were centered, with rivers swollen
by melting snow and torrential rains
washing away bridges and villages. The
area seldom has knownrsu q drench-