How is silver iodide used in cloud seeding?

In the context of weather modification, silver iodide is used as an effective agent for seeding supercooled clouds to induce precipitation.12

Supercooled clouds consist of water droplets that remain liquid at temperatures below 0°C due to their purity. When these clouds lack sufficient natural ice nuclei, they can remain stable without producing rain or snow. Silver iodide is introduced into these clouds to act as artificial ice nuclei, triggering the formation of ice crystals that grow and eventually fall as precipitation.1

Techniques for dispersing silver iodide include:

• Burning solutions: Silver iodide is often dissolved in a sodium iodide-acetone solution and burned at high temperatures (approximately 1,100°C) to produce vast quantities of minute particles, ranging from 0.01 to 0.1 micrometres in diameter.1
• Dispersion methods: These particles are released into the atmosphere via ground-based generators, aircraft-mounted generators, or pyrotechnic devices dropped into clouds.1
• Projectiles: In some historical programs, rockets or artillery guns were used to deliver silver iodide directly into specific cloud regions.1

Once dispersed, these particles facilitate the freezing process, helping to increase snowpack or rainfall in targeted areas.12