Seeding Equipment

Silver Iodide ground generators release microscopic particles in or below cloud base which act as a nucleus for ice crystals to form, spurring precipitation development.

Airplane-mounted seeding generators are used primarily on summer cloudseeding programs and a few winter programs. They are operated either directly below cloud in the updraft, or in-cloud usually during winter operations in less turbulent conditions.

Burn-in-place, or end-burning flares emit a fine silver iodide smoke similar to that from ground-based or wing-tip mounted generators.

Gound-based propane generators work by virtue of propane's extremely cold temperature. They instantly condense and freeze liquid water droplets in super-cooled clouds.

Hygroscopic flares like these are used in a similar fashion to silver iodide flares, but supply clouds with condensation nuclei to grow raindrops without the need for a freezing process.

Dry ice pellets are used on some cloud seeding programs. They are typically dropped by airplanes in convective clouds during summer seeding programs to induce ice formation earlier than it would occur naturally. Dry ice acts differently than silver iodide as it simultaneously creates and then freezes supercooled droplets by virtue of its extremely cold surface temperature. To see a demonstration of how dry ice seeding works, go to the Seeding Methods section on this web site.

Ejectable flares are dispensed directly into growing cumulus clouds. The "candle" that is ejected contains approximately 20 grams of seeding material and burns completely in less than one minute, distributing the silver iodide nuclei inside the cloud.