Silver causes precipitation

When a cloud is seeded with silver iodide, water vapour collects around the added particles and becomes liquid (as droplets) or freezes solid (as ice). Finally, the heavy silver iodide cores fall as rain or snow.

MONSOON BOOSTS COMBUSTION CHAMBERS

1 Weather satellites monitor the monsoon, which carries moist air inland from the Indian Ocean. As the monsoon approaches the Tibetan Plateau, scientists activate combustion chambers to produce silver iodide.

THE WIND CARRIES SILVER IODIDE TO THE CLOUDS

2 In the rising warm air from the combustion chambers and aided by the wind, the silver iodide particles are carried into the clouds. Radar monitoring has revealed that even a light breeze can lift the particles 1+ km.

SILVER IODIDE PRODUCES WATER DROPS AND ICE CRYSTALS

3 The silver iodide particles have the same structure as ice crystals. The chemical functions as a kind of magnet, attracting, collecting, and condensing the water vapour into liquid droplets or ice.

ARTIFICIAL PRECIPITATION FALLS FROM THE CLOUDS

4 When the drops or ice crystals have grown sufficiently heavy, they fall from the cloud as rain or snow. Sometimes, the precipitation falls immediately, but 15-30 minutes could pass, before it begins.