Abstract: A device for producing an airborne stream of ice crystals, the device comprising an inner housing mounted within an outer housing to define therewith an air passage having a venturi-shaped zone. A flaring nozzle is mounted to an outlet end of the outer housing. A vaneaxial fan is mounted in the outer housing and cooperates with guide vanes extending between the inner and the outer housing to produce a substantially rectilinear air flow through the passage. A diffuser is mounted adjacent an outlet end of the inner housing for creating an annular and rectilinear stream of air surrounded by a diverging stream of air. A water nozzle and nucleators are mounted in the outlet end of the inner housing to produce water droplets sprayed in the air streams, which freeze to form an airborne stream of ice crystals.