WMOD00568

• Project Name: Snowater
• Title: Snow Water Augmentation for the Eastern Slopes of the Rockies - Stage I: Technology Adaptation
• Date: 6/1/1986
• Weather Modification - Doc Type: Report

..._ .._............._ ..__..,"~_ .~t~~,-..!....

--...-.,...............---1

I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I

two week field programs from 1982 to 1984 to measure the properties of
clouds over the southern Canadian Rockies. These field measurements
included over 100 hours of observations made over eleven days.
Measurements were made using a variety of airborne instruments.
Climatological studies of ice crystals and precipitation particles,
supercooled cloud liquid water contents, cloud droplets and vertical
air motions were completed. Estimates of the precipitation efficiency
of the clouds were also made.

Results indicated typical ice crystal concentrations of 1 to 7 per
litre, with crystal diameters of 200 to 400 microns. Approximately
50 percent of liquid water values were above 0.1 grams per cubic
meter, with peak values greater than O.S grams per cubic meter.
Evidence of an increase in cloud liquid water contents near barrier
peaks was found. Estimates of the precipitation conversion efficiency
for three selected cases indicated values from less than 1 percent to
16 percent (Barlow et al, 1986). These results suggest that available
liquid water was not being efficiently converted to precipitation and
that the precipitation process could be made more efficient if
artificial ice nuclei were added.

These first aircraft measurements of winter orographic clouds made in
Canada are consistent with those reported from projects in the western
U.S. They indicate sufficient supercooled liquid water occurs in
winter orographic clouds over the Southern Canadian Rocky Mountains to
permit enhancement of precipitation through cloud seeding.

Application of orographic cloud seeding principles to Alberta requires
special geographical and meteorological considerations. The
Continental Divide constitutes the boundary between Alberta and
British Columbia. Hence, a target area could include watersheds in
both provinces or in Alberta alone. Seeding systems could be located
entirely in Alberta if desired. In southwestern Alberta, prevailing
mid-level winds are westerly. When this occurs, seeding systems must
be located to the west of the target area. Significant cloud also
develops with easterly low and mid-level flow. In this case, seeding
systems must be located to the east of the target area.

2.4 SNOWATER PROJECT STRATEGY AND COMPONENTS

SNOWATER I would follow a research strategy detailed by a
comprehensive Experimental Design Plan to be developed during the
initial months of Year One. Field Operation Plans would be drafted
prior to the initiation of field studies. These planning documents
would be updated annually to reflect enhanced scientific understanding
derived during the project operations.

The project would be planned to make cost effective use of existing
resources and expertise. Close cooperation with Provincial and Federal
government agencies would be maintained. It is anticipated that a
significant part of operational and support studies would be
contracted to the private sector and the universities.

2-4