BKMLancastar Farming, Saturday, January 1, 1994
After slogging through it, being
stuck in it and even dying from it,
you’d think that human beings by
now would know everything there
is to know abojut snow. Not so.
Solid, liquid and gas at varying
times, snow is a complex sub
stance whose behavior on land
and in the air still eludes scien
tists. Wet snow is an entirely dif
ferent material from dry snow, and
within the wet and dry categories
are numeorus different types.
When snow hits the ground, it is
no longer the same substance that
has been falling through the atmo
sphere. And fallen snow, a good
insulator of the soil it blankets,
undergoes constant change.
What happens to snow on the
ground - how it bonds, breaks
apart, melts and refreezers - mat
ters for everything from avalanche
prediction to the design of better
performing tires for military tanks
and private cars, safer skis for
airplanes, faster skis for people,
more effective but environmental
ly correct deicing chemicals for
highways and “grooming” tech
niques for smoother, longer
lasting snow roads and snowmo
bile trails.
The end of the Cold War has
melted some snow-cover research,
says Russell Alger, director of the
Institute for Snow Research in
Michigan’s Upper Peninsula.
Except for Bosnia in winter, the
big push now militarily is for
improved vehicle mobility not
in snow, but in desert sand.
More than 95 percent of Earth’s
seasonally snow-covered land lies
in the Northern Hemisphere,
which holds most of the planet’s
landmass.
From December through
March, the white stuff blankets 16
million to 20 million square miles
of the hemisphere, the majority of
the land north of 40 degrees lati
tude. By midsummer it all disap
pears, except for glacial snow and
ice fields.
Since 1972, satellite images,
which have provided the first con
sistent record of snow coverage,
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Snow, which covers more of Alaska than any other U.S. state, blankets an aban
doned copper-mining camp In the Wrangell Mountains. The deepest seasonal snow Is
found In Southeast Alaska and Washington state. More than 95 percent of the earth’s
snow-covered land lies in the Northern Hemisphere.
There’s More To Snow Than Snow
have shown that the year-to-year
horizontal expanse of winter snow
has not varied significantly across
the Northern Hemisphere as a
whole.
“But the snow has melted ear
lier in the spring in the past six
years in March and April,
rather than April and May,” says
geographer David A. Robinson of
Rutgers University in New Jersey,
who has analyzed the satellite
data.
“The biggest change in recent
snow cover is not so much its lack
in winter as its early end, its
reduction in spring,” agrees Ken
neth F. Dewey, professor of cli
matology at the University of
Nebraska.
Why the early spring snow
loss? Scientists aren’t sure.
“There is a strong correlation
between temperatures in the
Northern Hemisphere and the
extent of snow cover,” says
Robinson. “Does recent warmth in
spring cause the early end of snow
cover, or does the early snow loss
have a subsequent impact on
temperature? Once you have the
loss, it kind of snowballs.”
Researchers are “trying to
unravel this chicken-and-egg
question,” Robinson tells National
Geographic. “It is too early the
record is too short to attribute
this to global warming."
While snow coverage has not
changed much globally, snow
depth may have decreased. There
is no similar satellite record,
because the current technology
cannot yet distinguish different
snow depths.
“Monitoring snow cover may
give an index to future climate
change,” says Robinson. “Snow
has to be an important piece of the
climatological puzzle.”
Earth loses a good portion of its
heat from the reflection of sun
light off snow.
Snow on the ground, especially
fresh snow (the whitest), reflects
back about 90 percent of sun’s
rays, says Samuel C. Colbeck, a
senior research scientist at the
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Etching new trails In spring snow, expert skiers swoop down the Canadian Rockies
in British Columbia. Scientists study what happens to the white stuff, which changes
constantly on the ground, to improve avalanche prediction and to design faster skis,
better-performing tires and safer de-icing chemicals.
U.S. Army Cold Regions
Research and Engineering Labor
atory in Hanover, N.Y. “The more
snow cover, the more solar radia
tion is relfected back.”
To fit another piece into the
weather puzzle, Dewey is analyz-
ing satellite data of Southern
Hemisphere snow cover for the
first lime to determine whether it
is in phase with the Northern
Hemisphere’s. About 800,000
square miles of the Southern
Hemisphere, mostly in South
America, is snow-covered
seasonally.
Although it may seem odd, it
hardly ever snows in Antarctica,
Earth’s driest continent. Antarciti
ca gets less than 2 inches of new
snow a year.
Batteries Going Green
ioy Eschenbach
National Geographic
News Service
WASHINGTON, D.C. ‘Tis
the season to buy batteries not
to figure out how to get rid of
them.
During the holidays, gadget
crazy Americans grab up the
largest percentage of the 2.5 bil
lion household batteries sold in
the United Stales each year.
It’s not just gift-giving that
boosts sales of these small techno
logical wonders that inevitably
wind up as toxic trash. Dark wint
er weather demands fresh batteries
for flashlights and helps put the
annual charge into the dry-cell
battery market
Mote than 90 percent of house
hold batteries are non
rechargeable and most will end up
in municipal dumps or incinera
tors. As the casings decay, their
potentially toxic contents, particu
larly mercury and cadmium, could
leak from landfills and thence sink
into underground water supplies.
Or, the poison could fall to the
ground from incinerator stacks.
But batteries by nature cap
sules of chemicals are now
“greener” than they’ve ever been.
Manufacturers are taking the
heavy metals out of many of them.
To promote environmentally
correct batteries, a number of
states have banned the use of mer
cury, A handful of cities and coun
ties are encouraging safe disposal
by collecting dead batteries by the
bucketfuls.
Eveready’s Energizer alkaline
battery boasts: “Mercury not
included.” Duracell too has re
engineered its alkaline batteries to
eliminate the substance. The
world’s two biggest battery manu
facturers say that means that their
most popular types of household
batteries contain no added mer
cury apart from trace elements
that naturally occur in any battery.
“We believe it’s smarter to
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avoid harmful materials in the first
place, rather than worry about dis
posal later,” says Eveready’r
Keith M. Schopp.
In 1992 Eveready introduced a
no-added-mercury zinc-air
hearing-aid battery to replace mer
curic oxide ones that woe 35 per
cent mercury.
Button-cell batteries, like those
used in calculators, contain the
most mercury. Mote and mote
camera batteries are being made
of longer-lasting, less-toxic
lithium.
“It’s better for the environment
that the mercury is out, but that
doesn’t mean batteries are innocu
ous,” says Juliet Rogers of the
New York-based Natural Resour
ces Defense Council. ‘There are
still metals in there that are going
to be leached out”
Like the disposable batteries,
the rechargeable varieties, used in
camcorders, power tools and port
able vacuum cleaners, now con
tain less than .025 percent mer
cury. But the cadmium in the
rechargeables has increased,
Rogers tells National Geographic
except for a new type made by
Rayovac that is alkaline instead of
nickel cadmium.
Batteries that can be recharged
300 to 1,000 times have reduced
landfill waste. But when eventual
ly discarded many still sealed
within the product they put
hundreds of tons of highly toxic
cadmium into the environment
every year.
Some environmentalists say
that no battery of any type should
enter the waste stream. But
because of the expense and logis
tical problems, very few batteries
are recycled nationwide.
Federal hazardous waste reg
ulations exempt household trash,
which is governed at the munici
pal solid waste level.