BOARD01023

• Board Meeting Date: 7/8/1959
• Description: Minutes
• Board Meetings - Doc Type: Meeting

.LO'J:'J:

MR. McCANDLESS:

MR. SCHLEUSENER: .

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MR. McCANDLESS:
MR.. SCHLEUSENER:

,

say, the most common occurrence of heavy
precipitation in the area which would in-
volve the development of a squall. line or
by a fellow system'moving into the area
from the northwest. Typically ahead of
that kind of a'system, winds will be from
the south where silver iodide will be car-
ried from south towards north so a control
area towards the south, on the average,
would be relatively free of nuclei. I
can't guarantee it's going to be free all
of the time.'~

I

"I would like to ask one question. This
term 'hail suppression' does that mean, or
I would think it would mean, that you en-'
deavor to get the moisture out of the clouds
before it gets a chance to freeze. Is that
the idea?"

"If you have only a small number of particles
on which that moisture can condense, then,
as the particles are developed and as they
are moved back and forth through.the clouds
at freezing temperatures, then you will get
a relatively small number of large particles.
If, on the other nand, you take the same
quantity of moisture that will be available
in the cloud and distribute those over a
larger number6f particles, then the indi-
vidual sizes should be smaller. So the
theory' behind the seeding says that if
you get enough of this particular matter
'into the cloud, individual sizes should be
smaller than they would be in the absence
of that seeding effect."

"Smaller hailstones, you mean?"

"Yes, that's correct. They are at-
tempting to suppress all hail so they will
seed every cloud that looks like it is a
potential hail bearing cloud. Of course,
if you have a given size of a stone, let's
say a quarter of an inch at 10,000 feet, the
chances are 'excellent. that it will be
melted by the time it reaches the ground,
therefore the smaller the stone the better
the chance it will be melted before it
reaches the ground.

I

On numerous occasions they have re-
ported hail in the air, and, if course, if