Trending Positive

The Southwestern Water Conservation District (SWCD) hosted a Weather Modification Work Session on May 30th in Durango. Participants and presenters from both the Upper and Lower Basin States were in attendance. After welcome and introductions, Larry Hjermstad, with Western Weather Consultants (WWC) provided a 2012-2013 operations summary. WWC provides cloud seeding services for the west slope and the southwest basin in particular. Among other updates, Hjermstad reported that WWC had: provided 500 hours of seeding with a budget of $336k; for a full winter of seeding, funding levels should be in the $450-$500k range (which is why Bruce Whitehead, SWCB Executive Director—stressed the need for additional and consistent participation in the program); and huge increases in the price of silver iodine. He reported that, “winter has been squeezing in from both ends.” As an example, past or historical winters usually began about the 10th of October—that start is now a month later. In addition, big snows and snow events would generally end in April, but that is now the month of March. In addition, he reported that the earlier change in runoff is more pronounced in dryer versus wetter snow years.
 
Joe Busto, with the Colorado Water Conservation Board (CWCB), provided an overview and update of their involvement in state weather modification efforts, including new rules and regulations, program evaluation, and plans for the 2013-2014 season. Joe reported that generally about 10 winter storms per year generate approximately 70% of the state’s water and 80% of Colorado water comes in the form of snow. He reports that research is indicating that: clouds should be seeded about a half hour before a storm; precipitation increases about 8% with cloud seeding; liquid propane should be used as the source in November, with silver used from December to March,  and it appears either would be just as effective in April. Joe reported that the state and the southwest basin in particular is in desperate need of additional radars (about $2 million each), not only to improve the weather modification program by being able to more accurately predict storms and which ones to target for maximum impact, but to enhance emergency preparedness and response efforts, as well. It was agreed by most in attendance that this should be a high priority action. 
 

Among a few other speakers, there were representatives from the Wyoming Water Development Office. They have been conducting research on the effectiveness of cloud seeding for the past number of years. While their final results will not be in until next year, presenters indicated that preliminary numbers are “trending positive”—indicating that cloud seeding may have a positive impact on precipitation. It was announced that the Weather Modification Association’s fall meeting will be conducted September 18-19 in Grand Junction and their Annual Conference for 2014 would be conducted in Reno. Contact the SWCD for more information on the workshop.