sleet

Sleet is a form of precipitation consisting of small ice pellets that reach the ground. In meteorology, sleet typically refers to translucent or opaque ice particles about 2 to 5 millimeters in diameter that bounce when they strike surfaces.

Sleet forms when falling snow passes through a warm layer of air aloft, melting into raindrops, before encountering a shallow layer of subfreezing air near the surface. The refrozen droplets become ice pellets before impact. The resulting precipitation often accompanies winter storms and tends to occur when warm air layers are present but a shallow cold layer near the ground refreezes the drops.

Distinguishing sleet from freezing rain and hail helps forecast impacts. Freezing rain occurs when liquid droplets survive the surface layer and freeze on contact, creating a glaze. Hail consists of layered ice produced by strong convective updrafts in thunderstorms. Sleet is typically smaller and forms in stratified air masses, reducing visibility and icing roads, but it usually does not create the long-lasting glaze associated with freezing rain.

Forecasting sleet relies on analyzing vertical temperature profiles and surface temperatures, along with radar and observational data. It is most common in mid-latitude regions during winter, including parts of North America, Europe, and Asia. Accumulated sleet can make roads slippery and disrupt travel, while ice pellets generally cause less damage from glazing than freezing rain.