Precipitation in the form of balls or irregular lumps of ice, always produced by convective clouds, nearly always cumulonimbus. An individual unit of hail is called a hailstone. By convention, hail ha
s a diameter of 5 mm or more, while smaller particles of similar origin, formerly called small hail, may be classed as either ice pellets or snow pellets. Thunderstorms that are characterized by strong updrafts, large liquid water contents, large cloud-drop sizes, and great vertical height are favorable to hail formation. The destructive effects of hailstorms upon plant and animal life, buildings and property, and aircraft in flight render them a prime object of weather modification studies. In aviation weather observations, hail is encoded A.
Precipitation of small balls or pieces of ice (hailstones) with a diameter ranging from 5 to 50 mm, or sometimes more, falling either separately or agglomerated into irregular lumps. When the diameter
is less than about 5 mm, the balls are called ice pellets.
Precipitation of small balls or pieces of ice (hailstones) with a diameter greater than 5 millimetres, falling either separately or agglomerated into irregular lumps.
Hail is a solid form of precipitation that has a diameter greater than 5 millimeters. Occasionally, hailstones can be the size of golf balls or larger. Hailstones of this size can be quite destructive
. The intense updrafts in mature thunderstorm clouds are a necessary requirement for hail formation.
Precipitation (falling) of particles of ice (hailstones). Usually spheroid, conical or irregular in form and with a diameter varying generally between 5 and 50 millimetres. Hail falls from clouds eith
er separately or collected into irregular lumps.
Precipitation of small balls or pieces of ice (hailstones) with a diameter ranging from 5 to 50 millimeters (0.2 to 2.0 inches), or sometimes bigger, falling either separately or agglomerated into irr
egular lumps; when the diameter is less than about 5 millimeters (0.2 inch), the balls are called ice pellets.
Precipitation in the form of balls or irregular lumps of ice, always produced by convective clouds, nearly always cumulonimbus. An individual unit of hail is called a hailstone. By convention, hail ha
s a diameter of 5 mm or more, while smaller particles of similar origin, formerly called small hail, may be classed as either ice pellets or snow pellets. Thunderstorms that are characterized by strong updrafts, large liquid water contents, large cloud-drop sizes, and great vertical height are favorable to hail formation. The destructive effects of hailstorms upon plant and animal life, buildings and property, and aircraft in flight render them a prime object of weather modification studies. In aviation weather observations, hail is encoded A.
A device used to obtain data on the size distribution and mass of hailstones. A hailpad usually consists of a plastic foam panel covered by aluminum foil or white latex paint and set in a frame that i
s hammered into the ground. Hail that impinges on the pad leaves dents in it. The dimensions of the dents are analyzed to obtain the hailstone size and mass data.
Part of an obsolete conceptual model of air parcel ascent referring to a portion of the ascent during which the parcel temperature remains at the freezing point until all the rain produced previously
has frozen. Other portions of the ascent were described as the dry stage, snow stage, and rain stage.
A single unit of hail, ranging in size from that of a pea to, on rare occasions, exceeding that of a grapefruit (i.e., from 5 mm to more than 15 cm in diameter). Hailstones may be spheroidal, conical,
or generally irregular in shape. The spheroidal stones often exhibit a layered internal structure, with layers of ice containing many air bubbles alternating with layers of relatively clear ice. These probably correspond to dry growth and wet growth and are called rime and glaze, respectively. The conical stones fall with their bases downward without much tumbling and are often smaller and not as layered. Irregular hailstones often have a lobate structure and are not composed of smaller hailstones frozen together. Hailstones grow by accretion of supercooled water drops and sometimes also by accretion of minor amounts of small ice particles. Large hail may contain liquid water and be spongy (an intimate mixture of ice and water) in some regions; it is usually solid ice with density greater than 0.8 g/cm^3. Small hail may be indistinguishable from large graupel (snow pellets) except for the convention that hail must be larger than 5 mm in diameter. The density of small hail can be much less than 0.8 g/cm^3 if they are dry; if partly melted, such hailstones become spongy. The largest recorded hailstone by weight to fall in the United States occurred in a hailstorm in Vivian, South Dakota, on 23 July 2010. The stone from this event weighed 870 g, with a diameter in excess of 20 cm.