WMOD00400

• Contract/Permit #: 14-06-D-6801
• Title: Structure and Seedability of San Juan Storms
• Date: 11/1/1976
• Weather Modification - Doc Type: Report

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was exposed for timed intervals during snO\-1fall periods furnishing some

valuable information on precise snowfall rates.

C. W.S.S.I. Data
1. SnO\o1fall

l~estern Science Services, Inc. (W.S.S.I.) operated ~30 precipitation gauges

over the San Juans as part of the San Juan Project. These data were always

made available for each storm studied as soon as they were available. The

data are discussed in Hartzell et al. (1975) and Hartzell and Crow (1976).

They \o1ere plotted and analyzed as part of the synthesis of each storm. The

important characteristics of the snowfall are summarized in each case study.

2. Ice .Nuclei

W.S.S.I. also operated Bigg-Warner ice nucleus counters at Pagosa Pines

and Piedra (both near Pagosa), and at Wolf Creek Pass. These data were

examined carefully for each seeded storm studied and several plots of the

data are presented in the case studies.

D. E.G. & G. Data
E.G. & G. conducted the seeding operation for the San Juan Project. The

seeding logs ,vere provided for each seeded storm studied. As part of their

operation they released rawinsondes from the Durango airport at three-hourly

intervals during all randomized case studies. In addition, they made three-

hourly soundings on storms flown by the research aircraft if the storm was

not one of the randomized c.ase studies.

The other set of data collected by E.G. & G. which proved especially

valuable in understanding the storm structure and its evolution with time

\.;ras surface winds. E.G. & G. had 10 to 12 'vind stations located between,

Wolf Creek Pass and Farmington. These data were telemetered in real time

at three hourly intervals to the E.G. & G. forecast office in Duiango.

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