Freezing rain is rain that freezes when it touches roads, trees, power lines, or other surfaces at or below 0 °C.
It usually forms when snow melts while falling through a warm layer of air, then passes through a shallow layer of freezing air near the ground. The drops remain liquid while falling but become ice immediately upon contact. This creates a smooth coating called glaze.
Freezing rain can make roads extremely slippery and add substantial weight to branches and utility lines. Even a thin layer can cause hazardous travel, while heavier ice accretion can produce power outages and tree damage.
Freezing rain is different from sleet, also called ice pellets in some regions. Sleet refreezes into solid pellets before reaching the ground. Hail forms inside strong thunderstorms and is produced by repeated rises and falls within a storm cloud.