Why can calcium chloride particles help form raindrops in warm clouds?

In meteorology, calcium chloride particles are used in the seeding of warm clouds—those with temperatures above 0°C—to encourage the formation of precipitation.12

These particles act as cloud condensation nuclei, providing surfaces upon which water vapor can condense. By introducing these particles into a cloud, meteorologists aim to produce "giant" cloud droplets. These larger droplets grow through the process of coalescence, where they collide with and absorb smaller cloud droplets as they fall. As these droplets increase in size, they eventually become heavy enough to fall from the cloud as raindrops.123

This method is distinct from seeding supercooled clouds, which typically involves using ice nuclei like silver iodide to trigger the formation of ice crystals.14