Vail Mountain and Beaver Creek fired up cloud seeding generators earlier this month to prepare for the 2004 to 2005 ski season.
"We believe it increases snowfall throughout the season by up to 10 to 16 percent," said Jen Brown, Vail Mountain communication manager.
Vail has been cloud seeding its slopes for nearly 30 years.
Cloud seeding, while not an exact or proven science, is the attempt to produce increased snowfall using generators that put a silver iodide solution into the clouds.
"Essentially we cannot tell the difference between a snowflake that has come from a silver iodide crystal and a snowflake from a natural ice crystal," said Larry Hjermstad, manager of Durango-based Western Weather Consultants.
Vail purchases the cloud seeding service from Hjermstad's company which contracts with local ranchers west of Vail who host the cloud seeding equipment on their property, Brown said.
"Vail usually begins seeding Nov. 1 to the end of January for about $165,000 using 17 cloud seeding generators," Hjermstad said. "All of our 17 generators are located upwind of Vail and Beaver Creek at various distances, usually about 12 to 25 miles to allow for stronger or lighter wind speeds which allows time for the crystals to be lifted into the cloud system and begin growing before reaching the target area."
Some resorts will use traditional snowmaking machines to increase the snow base on the slopes.
Brown said Vail spends approximately $1.6 million annually on snowmaking.
"For Vail, cloud seeding is a good investment because when you compare the cost of snowmaking to cloud seeding, cloud seeding clearly is significantly more affordable," Brown said. "Snowmaking covers only 390 of our 5,289 acres of terrain and occurs mostly in high traffic areas, and uses a lot of water."
But not all ski resorts in Colorado chose to chance cloud seeding's inexact results.
"Cloud seeding is tough to put a value on at this stage. There is no concrete way to gauge whether or not it works and it's a hefty investment for a ski resort in terms of spending based upon return investment," said Emily Jacob, Breckenridge Ski Resort communication manager. "If (Breckenridge) could evaluate the cloud seeding program based upon concrete evidence and that evidence proved that cloud seeding was a viable option, (Breckenridge) would certainly take a closer look."
Although there is no scientific evidence as to the benefits of cloud seeding, Brown said Vail has attempted to study the profit of cloud seeding.
"A few seasons ago (Vail) analyzed snow fall records for all Colorado ski resorts through avalanche center recorded amounts, and based on that analysis we reached the conclusion that Vail and Beaver Creek showed snow fall amounts per storm, and collectively (Vail and Beaver Creek) were receiving 8 to 25 percent more snow in any cycle that we were seeding than the average other resorts were receiving," Brown said. "The average over the study was approximately 16 percent increased snowfall."
Resorts pondering the idea of cloud seeding must weigh the evidence for and against the process and decide whether cloud seeding is a costly benefit or a costly detriment.
"At this point, for Breckenridge, we will continue to put our financial resources into snowmaking, which is an important operation for our sustainability throughout the season," Jacobs said.