contained developingrequest, we directed
on the types of chemicals
storms, and
for conducted
your
WASHINGXJN. O.C. 205.48
13-100063
This 1971, for
Schweikcr:
LM096545
is in certain
carried the
response to background
your request informatio-n
of September 22, on cloud-seeding
.2-o xz2-
activities supported-by questions toward ported progrys,
and severe
seeding and their effect
out Federal
in
in the .Unitc.b_S~.~-~,.under -…- -..T—* programs the specific our:review programs sup- agencies. Pursuant to information —–a-=v-~.,-, on cloud-seeding L-..-”-.- , ._
by
agencies,
on the cost- ‘and purposes
of such
Federal
on the impact of cloud seeding on precipitation
on the–environment. the extent of cloud
used
also ob-
tained over
dafa cdncerning Pennsylvania.
We seeding
Federal
D.C., and
and Montana. reviewed
Our review was conducted agencies headquartered
at various Washington,
departments ’
and
tain
terviewed
records
pertinent
for Science and Technology, the and the National Water Commission.
BACKGROUND AND COST DATA
at cer- We in-
of
their field offices cognizant agency
in in
Colorado officials
and
appropriate we reviewed
and files of the
reports and documentation
agencies.
In
of National
addition,
the Federal
Academy
Council
of Sciences,
Several Federal
programs which search programs cloud modification, ricane modification.
Statistics for Atmospheric
agencies support cloud-seeding
weather modification
involve include
compiled by the Interdepartmental
precipitation hail suppression,
activities. modification, and lightning
Major re- fog and and hur-
sored through fiscal
weather 1970
years
modification
rograms
‘74 million; %
According Federal weather
agency for fiscal
annual
years 1965 through
Committee, by research
totaled 1971
about and 1972
totaled about
$35 million.
Sciences showed that
costs for during fiscal estimated
Committee federally spon-
years 1959 costs for
costs for area and
follows:
to
modification activities
reports of the
1972 are as
.
dr
.. .
,
1
B-100063
Precipitation tion:
Interior Commerce National
Research areas
1968 to 1970 actual
—–(000
$13,888 1,983
1,050 16,921
1971 to 1972 estimated
Total –I $25,888 3, 87.1 1,600 31,359 7,021 2,225 4,122 775 14,143 7,700 926 8,626 1,422 1,257 711 299 3,689 3,153 450 3,603 $61,420 modifica- omitted) .c $.12,bOO 1,888 550 14,438 2,806 2,201 1,800 230 7,037 4,400 369 4,769 660 500 342 69 1,571 2,428 125 2,553 $30,368 Science Foundation (NSF) I * ‘I Total Fog and cloud modifica- tion: Defense Transportation 24 NSF National Aeronautics and Space Adminis- tration (NASA) Total Hail suppression: NSF 4,215 2,322 545 __–
7,106
3,300 Commerce 557
Total 3,857
Lightning modification:
Agriculture 762 NSF 757
Commerce 369 Defense 230
Total 2,118
Hurricane modification:
Commerce 725 Defense 325
Total 1,050 Total $31,052
2
..
f
- B-1.00063
Other research involving weather modification supported
by Federal agencies includes development of mathematical mod- els of atmospheric conditions; studies of inadvertent modifi- cation; and studies of legal, economic, social, and ecological aspects of modifying the weather. Costs for such research
for fiscal years 1971 and 1972 are estimated to total about $4.6 million.
Most .weather modification efforts ;are based on the use of seeding agents to produce artificial nuclei on whi,ch water vapor and supercooled water can freeze or condense a?d alter the physical processes within clouds. The effects of seeding on a particular cloud depend on, among other things, the tem- perature of the cloud, the number of nuclei present, and the area of the cloud in which nuclei are added. In addition to
being used for increasing and decreasing precipitation,
ing is used for influencing the type of precipitation electrical phenomena in the cloud. Such influence
the basis for research on hail and lightning suppression.
Various methods are used to seed clouds from either the air or the ground. In aerial seeding flares containing silver iodide, the most commonly used seeding material in the United States, are ignited and dropped from a plane, or propane gen- erators, attached to the wings of a plane, are used to burn acetone with silver iodide to produce nuclei which are deliv- ered at controlled rates into the cloud. Propane generators are also used to seed clouds from the ground. Ground-based generators depend on prevailing winds to carry the nuclei to the clouds. Aerial seeding is considered to be more accurate than seeding from ground generators because aircraft can bet- ter deliver nuclei to those clouds or parts of clouds where the seeding material is desired.
Costs for cloud seeding, which is an integral part of a Federal agency’s weather modification program, are generally commingled with other program costs and are not readily de- terminable as a separate cost activity. Seeding costs vary depending on the delivery system used. Aerial seeding, which makes extensive use of computers, radar, and aircraft, is generally recognized to be considerably more expensive than
seed- and the
provides
ground-based seeding.
the Air Force’s weather
exclusive of costs for
hourly cost for seeding
about $50 and for aerial seeding was about $647.50.
with that,
Air Force officials associated modification program estimated
the
personnel and capital investment, with ground-based generators was .
\ f
’
B- 100063
FEDERALLY SUPPORTEDWEATFlER MODIFICATION ACTIVITIES
Information fication programs
concerning involving
federa cloud-seeding
supported activities
tion and Precipitation
severe
below. – e
modificatibn
1972 are estimated
about $28
million.
fog, storms
lightning,
and hurricanes
hail,
are presented
of precipitation techniques to
and
research rain
re-
which was Interior’s out, in
trol precipitation,
any evidence of the impact that seeding has had on precipita-
lly
weather mod to con!-
The
is to study
or snow. search has Departments
purpose develop
Federal support been provided
general and
manage
and control modification
modification
of the
and Commerce 33
agencies–the NSF.
for precipitation principally by
Interior
the Tnte’rior
of the Interior under its
three and
supports Project Skywater,
is administered by
I
Department
of
The
modification research
Department initiated in 1962.
precipitation
Bureau large Costs year
of Reclamation,
part, by universities for Project Skywater
The
project
and
to total
of Project Skywater is to learn
areas by seed- Initially such
the research is under contracts
from its inception
carried with
Interior. through fiscal
The primary objective how to manage precipitation
ing orographic
in water-deficient (mountain-produced) clouds.
seeding field ducted
United were
involved experiments
winter storm clouds only.
on winter-storm-cloud seeding
Since 1963, 10
con- generators in
under
States. seeded
the
project Under
at various locations these experiments winter
iodide mainly by ground
have in the
been western
with silver to increase
storm
clouds
an attempt experiments
clouds cloud would
these limits.
has estimated that seasonal snowfall in the western States can be increased by 10 to 30 percent.
involving seeding Skywater started in
seeding of cumulus or urea to induce
would tops was decrease
snowfall approximately
when the
temperature
indicated increase
snowfall. According that seeding orographic
to
Interior winter
the storm
of the
snowfall when
between -12°C. and -22°C. and the temperature was outside
On the basis of these experiments,
Interior United
under involved salt,
aerial dry ice,
summer
- These experiments
Experiments Project
clouds rainfall. Such
cumulus
clouds with silver iodide,
additional .
f’
B- 100063
experiments included cloud seeding over Arizona,
and Texas in 1971 to alleviate
States. According cumulus-cloud-seeding
cipitation and in cipitation. Therefore
to date to be inconclusive.
drought conditions in some cases
Oklahoma, in those summer-
spheric
cation
clouds
its Great
In contrast orographic clouds and interactions
on
National Cumulus
clouds and Modification
Project,
winter Project
to other
Interior, experiments
cases Interior
resulted in
resulted considers
.z
the
it
increased pre- decreased pre-
results
*
ahd Atmo-
modifi- storm
in experiment
2/
Department of
The Department Administration
Commerce 7Y
of Commerce’s
(NOM) supports precipitation
National
Oceanic
research under its
summer cumulus Snow Redistribution
and
Lakes with
National rainfall
Interior’s
Cumulus Modification from tropical
respectively.
Project
which are produced
involves cumulus
clouds, winter
these stratus
projects clouds,
Skywater, concern tropical
which of water and air over lakes.
by the is aimed at
The increasing
Project cumulus clouds.
Experimen- conducted
Since
flares air- 1972
tal seedings
initially over
1968 such experiments have
of
to total
such clouds with silver iodide were
the Carribbean
Sea in 1963 and 1965.
Seeding
which
planes.
are estimated
project
directly costs
been conducted is done with
into suitable
over silver
Florida. iodide
under the are dropped
from according to
Project
fiscal years
clouds
1968 through
for
about $2.1 million.
The results dicate that seeded
these experiments,
clouds, on the average,
of
three times as much rain as unseeded clouds.
NOAA, yield more than
mated that seeding
feet of additional
single clouds which
as much water as two singly seeded clouds which do not merge.
individual clouds yields water for each cloud and
in- 100 to 250 acre-
NOAA has esti-
that merge can yield approximately
seeding
20 times
two whether the seeding tech-
Howe ve r , it has
not been determined
niques developed be applicable
The primary
in
for other
tropical parts
cumulus of the
clouds country.
in Florida would
Snow Redistribu- which annually
tion Project hamper Buffalo, shoreli~ne of early in the
objective
is to alleviate
of the Great Lakes the heavy snowfalls
New York, Lake Erie.
and other
In 1968 and
cities 1963
located snowstorms
along the occurring
and dry ice
the nor-
winter were to redistribute
iodide inland
seeded
mal heavy accumulations along the southeastern
with
snow further
in an attempt
silver
from shore of
5 Lake Erie. plished to experiments under this estimated
Significant redistribution
has not been accom-
5
National
be
substantially experiments
winter Skywater
or seeding
” part,
The results the basis
conducted
research fog.
of for
under
has
The –
under certain
date through these were planned to project for fiscal
Science Foundation
experiments. continued
years 1968 million.
q.L
seeding 1972. costs
1972 are
be to total about $1.7
Similar through
through
s
modification
Colorado State University.
a cloud-seeding proj’ect University near Climax,
c
NSF has through grants,
supported
principally NSF has
precipitation to
research
I
which Col-
Since 1961 the was initiated by orado, in 1959.
Colorado
supported State
of delivered
grants totaled
The
tion Modification,”
orographic
clouds
mine
silver
1972 NSF University
the effects iodjde
from for winter-cloud about $1.3
the million.
National supported experiments
July at Climax
entitled 1971, stated that
The
objective seeding
of winter
the research was to
deter- with
ground. seeding
Through
to Colorado
fiscal year State
Water dated
Commission report
“Precipita- the NSF-
that
can these Interior’s Project
meteorological increased
have provided,
orographic in Colorado.
conditions decreased.
evidence precipitation
“offered conclusive
in
large research
Fog modification
The been to
principal study and
objective develop
of fog
methods for dissipating
y Department of research
of Defense has
concerning warm- and cold-fog
Federal dissipation. estimated
supporter 6 For
that costs
been the principal fiscal years 1968 through 1972 Defense has
modification
for such research
Defense’s above OOC.)
to promote
will
modification focused
total about $7 million.
program for warm on the development of
fog (temperature three techniques
has
the dissipation of
fog. Only one other techniques
air from above or with warm
to dissipate California
experiments
of these
are based on
by using the
air produced by
warm fog were con-
seeding
mixing
down\i:sh
ground-based burners.
Cloud-seeding experiments ducted by Defense in northern October 1969. Other seeding
involves
with
fog with drier, warmer
chemicals, The created by helicopters
October 1968 and
in
were conducted at r
I
B- 100063
McClellan Air Force Base, California, during January 1971. these experiments fog was seeded with salt or urea. Defense has had only limited success in developing techniques to dis- sipate warm fog.
To dissipate cold fog (temperature below O’C.), however, Defense has successfully developed techniques for aerial and ground-based cloud seeding with dry ice and propane, respec- tively. Defense intends to develop an operational cold-fog’ modification program for use, when necessary, at milgtary in- stallations.
In
Other Federal agencies which have supported fog modifi- cation research are the Department of Transportation, NSF, and NASA. Much of the research supported by these agencies has been laboratory related and has not involved cloud-seeding ac- tivities.
Hail suppression
Hail suppression research seeks to develop modification techniques that will restrict the size of hailstones and
that will thus reduce their damage potential. NSF has been the
lead agency for Federal support of hail suppression research, and the NSF’s cost for such research for fiscal years 1966 through 1972 is estimated to total about $7.9 million.
In 1966 NSF funded a l-year pilot field experiment–
Project Hailswath–in which hailstorms over South Dakota and Colorado were seeded with silver iodide and dry ice. Similar experiments were conducted during the period 1968 through
1970 under a project called Joint Hail Project.
In 1971 the NSF initiated a new research program called
the National Hail Research Experiment to study hailstorms over a target area in Colorado by using ground meteorological net- works, instrumented aircraft, ground and airborne radar, and other techniques. From these observations, mathematical mod- els of representative hailstorms will be developed and a num- ber of hail suppression techniques will be tested by computer simulation. NSF’s National Center for Atmospheric Research
at Boulder, Colorado, has primary responsibility for manage- ment of the experiment in which other Federal agencies, sev- eral universities, and private institutions will participate. Under the experiment exploratory seeding with silver iodide over northeastern Colorado is planned during five summer sea- sons beginning in 1972. B- 100063
Lightning
5 The /porter of
modification —.-
Department of Agriculture Yb is the major Federal sup-
lightning modification research.
Agriculture sup- which is
Skyfire
for their
ports such research under its Project
Skyfire Project technique3
administered by
tiated to test
effects on the
to develop methods to
the Forest Service.
was ini- thunderstorms and
various lightning
cloud-seeding characteristics
Project costs to total about not available.
Experimental under Project
for fiscal $1.4 million.
seeding
in
years
forest 1968 Project
caused 1972
by, 1.ightn’ing. are, estimated
prevent
of fires
through costs
silver Montana
research conducted
and 1965 continues, culture
Skyfire through 1967.
Although has been
1961, project
with western
iodide
prior
was conducted
1960,
the 1967.
in
have
strokes single
to 1968 were
during under
determine seeding light-
no seeding has noted that
the electrical
research number of
associated
the is
since process
Agri- clouds is
not that the thus forest more ning .
results
indicated and
and a
for
fully
seeding can reduce the
understood;
however, duration of the strokes
lightning with
a
storm cause
that specifically the predictable
lightning necessary
can lessen the chance
fire. Additional research
will to
effects
provided
In 1966
storms
These experiments
of
Other Federal agencies have lightning modification research.
limited
support
aerial seeding over Flagstaff, possibility that charged by chaff
of Arizona.
Defense with metallic
essary
to generate
lightning.
lightning
electrical seeding
fields before they
in
storms reached
supported nylon chaff
indicated the
could be dis-
the strength nec-
toward develop-
Commerce has
ing lightning detection techniques niques for artificially triggering
directed and toward lightning.
supported laboratory tween cloud electricity
research to
and precipitation
the
and to explore the
supported research
exploring NSF has
tech-
relationship be-
possibility charges
Hurricane —
The
ricanc was conducted in 1947
examine
by injecting electrical
of inducing into clouds.
modification
rainfall
earliest cloud-seeding
experiment to modify a hur- under Project Cirrus, which was F’ ’
B-100063
sponsored by Defense.
not be assessed because, canes were not sufficiently
The at
results of the the time, the understood.
could of hurri-
Hurricane Project
by to
initiated
in 1956. This Defense. Project
was jointly was de-
experiment dynamics
To Research
better Project,
understand more
hurricanes the commonly referred
National
Stormfury
structure and dynamics of hurricanes
Stormfury,
funded
signed
and to develop a seeding technology to reduce the maeximum sur-
to as project
was
Commerce and explore the
face winds associated with under the project during
hurricanes. fiscal years
Costs to
be incurred 1972 by
$3.1 million the project
*
Commerce
and $450,000, respectively. Cost prior to 1968 was not available.
1968
to information
through about for
and Defense are estimated
total
Under Project Stormfury, fdur hurricanes–all Coast–were seeded with silver iodide.
on the
In 1961 Hur-
Atlantic
ricane Esther was seeded, and in 1963, 1969, and 1971 Hurri-
canes Beulah, Debbie, According to Commerce,
and Ginger, decreases
respectively, were in the wind velocity
seeded. of
the var-
seeded level iability
hurricanes were
noted
were winds.
in these within the
experiments, range of additional
but natural
of the of
decreases hurricane
Therefore
determination could
research be made
by
was necessary
as to the degree to seeding.
a definite
which hurricanes could be modified
before
ECOLOGICAL EFFECTS OF CLOUD-SEEDING AGENTS
monly Other vate
lic
used chemical
seeding agents seeders include
nylon chaff.
in weather modification
the most com-
As noted earlier, silver iodide has
been experiments.
which salt,
use of Effects
have been urea, dry
used ice,
by public propane,
and pri- and metal-
Regarding the entitled “Ecological
silver iodide
of Modification:
for seeding,
A Problem
a report
Analysis ,” dated May 1969 and sponsored by Interior, states
that “all environmental ever, the VC?T, which,
available evidence indicates
little likelihood in silver iodide.
consequences
the most toxic of
of
How –
sil-
report
in
effects” from the iodine notes that the possible
is one of resolved.
iodide as humans because
of
some respects,
are not so easily
heavy
cates
sents
concentrations of silver
metals,
that the use of silver no direct hazard to
The report indi- a seeding agent pre-
the immediate
and iodine in the air and rainfall
9 c
13-100063
will be exceedingly rare exceptions,
cipitation Public report
‘fJ;J;k
small. The report
points out less silver
that, with in pre-
the U.S. Thus the
from
Health Service
standard for drinking
water.
states that: Preliminary
indications are that harmful levels through
it will either
not ter-
there seeded
is substantially
storms than is allowed by
concentrate
restorial
environmental
does not seem great enough to preclude its use at
to
aquatic food chains. The
threat
iodide ‘,
this time. problem,
According
should be given
on fog modification
to
or
Close attention however.”
of the
contamination from silver
ects, salt life and areas or that urea surfaces,
to plant
Dry Manager
to Defense is corrosive
to
reports
metals and
detrimental seeding
reports
proj- plant
therefore
is
not
runways. These and noncorrosive
for it
in also
to populated
over is
and life.
airport nontoxic animal
practical tissue and that
to is
metals, highly
indicated protected beneficial
ice
for NSF’s ecological
liquid weather
Program
no known
Con- that
which
and
propane, according
modification program, have
to the
adverse
cerning
chaff
have no known adverse ecological
metallic aluminized
effects
nylon chaff, .the Program
is
CLOUD SEEDING OVER PENNSYLVANIA
which effects.
nylon threads
when used as
seeding-agents. Manager said are inert and
In quiring
1967 the State State licensing
of Pennsylvania and regulation
enacted legislation
of weather modification
We interviewed cog-
re-
activities nizant weather respective ments over Also, an
carried out in Pennsylvania.
officials of modification
agencies
Pennsylvania official of
seeding.
trust that the above information is responsive to We have previously returned the material on cloud
various research,
had not
Federal and
supported enactment
agencies that
sponsor
that their
from Pennsylvania
they
advised cloud-seeding
us
of the legislation.
Department
for administering the requirements
of Agricul-
of the law, told us that the State had not issued any licenses
the which is responsible
experi-
ture,
for cloud
We
your
needs.
10
1, 17
. .
B-100063
seeding that your office made available for our use in this review.
Sincerely yours,
.-J–,4 p g–y.,x+d
Comptroller General *
of the United Stakes *
c( 4s ‘Ihc Honorable
.A United States Senate
S. Schweiker
Richard
11