Definition of reservoir. 1 : a place where something is kept in store: such asa : an artificial lake where water is collected and kept in quantity for useb : a part of an apparatus in which a liquid is heldc : supply, store a large reservoir of educated people.
All three involve precipitation in the clouds, but each requires just the right set of circumstances to occur. One difference between sleet and hail is the time of year in which each occurs. Typically, hail is most often a summer occurrence, while sleet occurs mostly in winter. Youâre much more likely to see hail in warm and oppressive weather where a sudden thunderstorm occurs.
Sleet is much more benign. Sleet forms when precipitation starts falling out of the clouds as snow, but encounters a warm layer of air (above freezing) on the way down. The snow melts into rain, but then the rain falls into a colder layer of air near the ground (below freezing). The rain freezes back into ice pellets.