The Sacramento Municipal Utility District is using aerial cloud seeding over El Dorado County to coax as much moisture out of passing storms as possible. The pilots fly into the tops of clouds looking for temperatures between 5 and 22 degrees, the temperature at which water vapor will form on the particles released by the plane. Behind each wing are arrays of flares which are lit to release billions of silver iodide particles. The microscopic particles act like crystals to form snowflakes and icy water drops. A team of four pilots fly out of McClellan Airpark in Sacramento using three modified Cessna-340 airplanes to do the job.