QUIZ: How much more snow falls after cloud seeding? A) 5-15% B) 25-50% C) 55-75%
ANSWER: A) It’s difficult to quantify the effectiveness of cloud seeding, but one recent study shows that cloud seeding results in approximately 5 – 15% more snow per storm.
Most ski resorts make snow in the early ski season with snow making machines. In recent years, ski resorts are also turning to cloud seeding programs to boost early season snow and extend snowpack into the spring. There are at least seven programs in Colorado ski areas, including at Vail, Beaver Creek, Telluride, Wolf Creek, and Winter Park. But is it effective?
Cloud seeding has been around for more than 70 years, but recently the technology and equipment have improved, enabling more accurate cloud seeding decisions and improved effectiveness in cloud seeding. Ski resorts are collaborating with municipalities and the Colorado Water Conservation Board (CWCB) to advance cloud seeding programs statewide, and the CWCB offers grants to help fund some cloud seeding programs.
For cloud seeding to be effective, you first need clouds to seed. Not all clouds result in snowfall, so the idea behind cloud seeding is to give existing clouds a little boost. A radiometer detects the moisture content of the cloud and is one of the most innovative tools used to determine which clouds to seed. The most common methods to seed that ski resorts use are manual, ground-based generators and remote generators that utilize modern telecommunication technology and are effective in reaching high elevation and inaccessible areas. The generator then sprays silver iodide over a propane flame, which is carried into the clouds via natural air flow, giving the clouds’ super-cooled liquid water something to adhere to. Once crystals form and are heavy enough, they fall in the form of snow.
Despite the excitement and promise of big snowfalls, it’s tough to quantify the benefits of cloud seeding. Recent studies completed by the Wyoming Weather Modification Program Pilot Project show that seeding results in an approximately 5 to 15 percent increase in snow per seedable storm in a target watershed. So it is effective, but the amount of snowfall may not yield the return on investment that resorts hope for. However, seeding may be cheaper than acquiring water rights for snow-making machines.
The bottom line? As long as there is a demand for snow, there will be innovations in snowmaking technology. And cloud seeding certainly gives some ski resorts an edge.
Images: Copyright University Corporation for Atmospheric Research (UCAR)