WMOD00544

• Project Name: Project Skywater
• Title: Project Skywater - An Introduction to Rivers in the Sky
• Date: 12/1/1973
• Weather Modification - Doc Type: Report

OROGRAPHIC CLOUD SEEDING

OBJECTIVE: Increase the number of
snow crystals in naturally
deficient clouds in order
that all available cloud
water will be utilized to
grow the crystals. These
will fall to the ground thus
depositing most of the
cloud water.

METHOD: 1. Silver iodide is released from one or
more generators located on jthe upwind
side of the mountain range.
2. Silver iodide particles transform many
of supercooled cloud droplets into ice
crystals.
3. Ice crystals attract moisturEl from
surrounding droplets and gmw large
enough to fall to the ground as snow.

NATURAL MOUNTAIN CLOUDS

(Top temperature <140 to-90F)

15 to 50 MINUTES REQUIRED
~ FOR SNOW CRYSTALS TO
~., ..- .\\",,__, GROW AND FALL OUT
G ;";.;;-~;;-"''': ,'EviIPORAl:ION
(:.i-.,. *\\"" - '. ":>" REGI.CW
AlrFI.~~~

Relatively few snow crystals farm &. fallout, Mast claud water
remains aloft in the farm of tiny supercooled droplets

(Top temperature colder
than -g'F)

Air Flow
----:-'

~ -

Cloud is cold enough for many snow crystals to form naturally,
thus depositing mast of the cloud water on the ground,

SEEDED MOUNTAIN CLOUDS

(Top temperature (14010-9')

151050 MINUTES REQUIRED
FOR SNOW CRYSTALS TO
r\.t;'---:-, GROW AND FALL OUT
~ b*_;lt! -.
I:~. *'Ll! _ << ~VAl>oRATION
,;.. f :r:"'~' !.~ "*~\.. REuION
.' 0.'.... ... ......... .
Air Flow /k'i;~:*_'~*: *~" <.--:.-'---....
~~""'~>:.._,,\*' ;,. J
-.e"'_..., ~

SILVER 1001 DE
GENeRATOR
Many snow crystals form in seeded clouds, thus depositing
most I)f the cloud water on the ground,

(Top temperature colder
than .go F)

SILVER IODIDE
GENERATOR
Seeding very cold clouds produces excessive snow crystals, which
compete for available moisture, This limits their size which
prevents them from falling to the ground,

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