WMOD00133

• Sponsor Name: Western Weather Consultants, LLC
• Project Name: Cloud Seeding Analysis
• Title: An Analysis of Regional Snotel and Ski Area Precipitation Data To Evaluate Precipitation Changes Resulting from Ten Seasons of Wintertime Cloud Seeding Operations over the Vail Ski Area
• Prepared For: Vail/Beaver Creek Ski Areas
• Prepared By: Western Weather Consultants, LLC
• Date: 3/1/2001
• Weather Modification - Doc Type: Report

3. Analysis of Ski Area Data

· Seeding dates and times for each season identified

· Precipitation data from each site identified for each seeding
date.

).> Daily precipitation read usually from 4:00am to 9:00am daily.

· A wind direction category was assigned to each
precipitation observation date from operational data

);> Total set of seeded data (all six categories)
);> Category #l-Seeding wind direction 240 to 269 deg
);> Category #2-Seeding wind direction 270 to 294 deg
);> Category #3-Seeding wind direction 295 to 360 deg
);> Category #4-Seeding wind direction 240 to 294 deg
);> Category #5-Seeding wind direction 270 to 360 deg
).> Category #6-Seeding wind direction 240 to 360 deg

· From the total precipitation amounts for each wind
direction category and the total set of observations from
the regional ski areas, an estimated precipitation amount
was determined for Vail by mathematical and extrapolated
means.

· The estimated precipitation value for Vail for each category
and for the total data set was compared to the actual
observed value for that category as an estimate of the
precipitation change resulting from the seeding operations.

· Snow density data was also determined for each of the
wind direction categories and the total set and compared to
the actual Vail data snow densities for the same categories.
These snow density comparisons were evaluated for
differences and a pattern.