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6
on to be asevere winter with many
record lows in the normally balmy
southern states.
Snow reflects about 90 percent
of sunlight. Winters with a lot of
initial snowfall consequently cause
a sort of "snow feedback." Warm–
ing sunshine is reflected back into
space wbile colder temperatures
cause moist ai r to condense-thus
more snow or sleet. Winters are
intensified and longer.
Another phenomenon widely
accepted as a cause of our upset
weather is jet-stream locking . A jet
stream is a narrow, fast-moving
body of air about 6 to 1Omiles high
( 10-16 km) flanked by broader,
slow-moving currents of air. lt is
formed by an energy exchange pro–
cess that takes place when warm
tropical air meets cold polar air.
What has been happening is that
instead of the jet stream slowly
moving from area to area, it has
been, of late, locking into one posi–
tion for long periods of time. By
locking in one position, an area will
continue to experience the same
type of weather unt iJ the jet stream
finally moves. What causes this
process is a g roup of "blocking
highs" that keep weather chan–
neJed in an area until the highs sud–
den l y and inexpl icab l y b r eak
down.
This locking phenomenon was
what occurred in 1980 when the
U .S. experienced a devastating heat
wave that took more than 1,300
Jives. At the same time, South
Africa froze while Eastern Europe
was drenched by torrential rains.
The "Gr eenhouse Effect"
Man is also undeniably affecting
his environment and climate in
(Continued on page 42)
TROPICAL CYCLONE-
The ferocious
weather of 1982 is il/ustrated by these
historie photos of the March battering
and courageous response of the Kingdom
of Tonga in the South Pacific. Demolished
port facilities, massive damage to resi·
dences, uprooted fruit trees and inun·
dated croplands /eft Tonga with near total
loss of the kingdom's annual income.
Technica/, agricultura/ and financia/ help
from neighboring and distant countries
enabled Tonga to begin a two-year
rebuilding effort. Economic restoration
began with al/ hands devoted to replant–
ing the soi/ with root and leal crops.
The PLAIN TRUTH