CALIFORNIA IN BRIEF : SAN FRANCISCO : Cloud-Seeding Experiment OKd

Federal officials have approved plans for a major cloud-seeding experiment that will use liquid propane to help increase snow in the Sierra. “This is the first cloud-seeding project of its kind in the country that has used liquid propane to seed winter clouds to increase snowfall,” said Dave Reynolds, a Bureau of Reclamation consultant. Usually, cloud-seeding programs use silver iodide or dry ice to trigger snowfall, but under the experiment, ground-based machinery is used. Monitors on the ridges detect the amount of water in storm clouds, and when adequate water exists, the propane is released. The liquid expands to a gas, causing the air to chill and condense moisture that then falls as snow, explained state meteorologist Mark Heggli.