Freezing rain

freezing rain

Rain that falls in liquid form but freezes upon impact and forms a coating of ice on the ground and or exposed objects.
In aviation weather observations, this hydrometeor is encoded FZRA. While the temperature of the ground surface and glazed objects is typically near or below freezing (0°C or 32°F), it is necessary that the water drops be supercooled (supercooled rain) before striking. Freezing rain can sometimes occur on surfaces exposed to the air (such as tree limbs) with air temperatures slightly above freezing in strong winds. Local evaporative cooling may result in freezing. Freezing rain frequently occurs, therefore, as a transient condition between the occurrence of rain and ice pellets (sleet). When encountered by an aircraft in flight, freezing rain can cause a dangerous accretion of clear icing.

NOAA, 2005: Federal Meteorological Handbook No. 1: Surface Weather Observations and Reports. Office of the Federal Coordinator for Meteorological Services and Supporting Research, FCM-H1-2019, 101 pp. [Available online at https://www.icams-portal.gov/publications/fmh/FMH1/fmh1_2019.pdf.]

Federal Aviation Administration, 2021: Surface Weather Observing, Air Traffic Organization, JO 7900.5E CHG 1, 178 pp. [Available online at https://www.faa.gov/documentLibrary/media/Order/JO_7900.5E_with_Change_1.pdf].

Term edited 30 December 2021.

Precipitation in the form of liquid water drops that have diameters greater than 0.5 mm, or, if widely scattered, the drops may be smaller.