Snow Headwaters, Water Education Colorado The Snow Issue Spring 2024

 Have you experienced the sound of planes overhead and then a dramatic change in the weather? One possible explanation is the occurrence of cloud seeding planes and their intention to increase moisture.  In this issue of the Headwaters Magazine, Elizabeth Miller discussed the phenomenon of cloud seeding and its application in Colorado in her article "Let It Snow". She describes the process of snow formation in clouds this way: "Every snowflake starts with water drops and ice crystals on bits of dust and pollen in the atmosphere. When enough water vapor freezes around those aerosols, gravity pulls them down as snow" (p. 29).

According to the article, Understanding Snow, also in this issue, the snow accumulated in the Colorado mountains constitutes the state's natural reservoir that generates 80% of the state's surface water.  Measuring the amount of water produced from a snow event started as a manual process, physically recording the snow the skier or snowshoer encountered taking samples to estimate water content. Now, in addition to the manual methods, automated methods using telemetry, "Snowpack Telemetry (SNOTEL)(p. 15)", supplements the data. 

Back to cloud seeding. Scientist discovered that the introduction of silver iodide particles into clouds could increase the amount of moisture and snow. Silver iodide gets dispensed either via a plane or with on-ground equipment. Research on the amount of water generated from cloud seeding vary. Studies done by the University Corporation for Atmospheric Research, conducted in 2017, documented an increase of 5% to 30% in one seeding event. An article in the New York Times, Cloud Wars, recounted the use of the process in the Middle East with less precipitation results and reported that Israel, nationally, had abandoned the technique for increasing water volume. 

Miller’s article indicated that the State of Colorado had funded eight "weather modification programs" within the state, impacting water districts and ski areas. They include: Vail/Beaver Creek, Upper Gunnison, Grand Mesa, San Juan Mountains, two in the North Platte, and the St. Vrain and Left Hand Conservancy Program.  To monitor the amount of moisture generated, each of the above programs submits reports with the data that estimates the amount of cloud seeding, and an estimate of "how much cloud seeding changed their snowpack and others offering precipitation amounts for seeded and non-seeded storms" (p. 29). 

Funding for the project, approximately $1.5 million annually, California, Arizona and Nevada--the lower basin states in the Colorado River Compact--contribute close to one-third with the hope of increasing water volumes in the Colorado River. Andrew Rickert, Colorado Water Conservation Board's Weather Modification Program manager, viewed cloud seeding as one instrument that Colorado could employ. From the reports of the program participants, he estimated an increase in precipitation of 5% to 30%. The article has an insert picture with that projection. The author quotes Rickert as saying: "At $2 per acre-foot, that's just amazing bang for the buck" (p. 29). 

At a conference that I attended, I posed this question: "If there is a fixed amount of water, does cloud seeding take moisture from one area at the detriment of other areas?". The speaker responded that the question was under investigation. This article does not address that question. Other articles in this issue explain that ski resorts, specifically Eldora, hope that precipitation can be augmented by stored water in ponds created in geographic depressions and reservoir expansion, if there are no clouds to seed.