They consist of tiny, single crytals, whose concentration per cm3 is much lower than the concentration of droplets in warmer clouds. The condensed water in this cloud is enough to fill a large residential swimming pool. It is amazing that something this big and heavy can form from clear air within just a few minutes, but it is common in the atmosphere. The reason is that updrafts suspend the cloud particles. In the case of the cumulus cloud, a typical drop radius is 0.01 mm.
Larger droplets fall faster.
Strong updrafts of many meters per second are required to suspend raindrops or hail in a cloud. Precipitation-sized particles, specifically those with radii greater than 0.1 mm, often fall from a cloud. The cloud itself can survive precipitation falling from its base provided that updrafts continue to promote condensation within the cloud. Downward air motion will quickly dissipate a cloud, for downward motion leads to compression of the air and an increase in temperature, which causes cloud droplets to evaporate.