Producers: Hazel Stark & Joe Horn Host: Hazel Stark When liquid water evaporates or solid ice sublimates, it transform into the gas we know as water vapor. In the case of snow formation, the water vapor becomes super chilled far below the freezing point of water, so when it comes into contact with dust, pollen, or smoke, that water vapor instantly forms a microscopic crystal of ice in a process called deposition. Photos, a full transcript, references, contact information, and more available at thenatureofphenology.wordpress.com