Hail

Definition

Pellets of ice.

Description

When rising moist warm air in a Cumulonimbus (Cb) cloud becomes saturated and water particles form, these particles continue to be carried upwards by the rising updrafts, turning to ice. These small ice particles then descend where they meet and join together with water droplets and are carried upwards again by the updrafts in the cloud, freezing again to become an ice pellet or Hail The cycle continues, with the ice pellets getting larger each time, until, as the Cb becomes mature, the updrafts weaken and they are insufficient to carry the weight of the ice pellets. At that point the pellets fall to earth. Hail pellets can be as large as a golf ball and can cause considerable damage to aircraft whether on the ground or in the air.

In METARs and TAFs, Hail is abbreviated to GR (from the French “Grêle”).

Accident & Incident Reports involving Hail Damage

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