Hail Hail Hail is a form of solid precipitation. It is distinct from ice pellets (American English "sleet"), though the two are often confused. It consists of balls or irregular lumps of ice, each of which is called a hailstone. Ice pellets fall generally in cold weather while hail growth is greatly inhibited during cold surface temperatures. Unlike other forms of water ice such as graupel, which is made of rime, and ice pellets, which are smaller and translucent, hailstones usually measure between and in diameter. The METAR reporting code for hail or greater is GR, while smaller hailstones and graupel
Backscatter diameter of the target multiplied by its inherent reflective properties, provided the wavelength is larger than the particle diameter (Rayleigh scattering). Water is almost 4 times more reflective than ice but droplets are much smaller than snow flakes or hail stones. So the backscattering is dependent on a mix of these two factors. The strongest backscatter comes from hail and large graupel (solid ice) due to their sizes, but non-Rayleigh (Mie scattering) effects can confuse interpretation. Another strong return is from melting snow or wet sleet, as they combine size and water reflectivity. They often show up as much higher