Precipitation in the form of very small, white opaque particles of ice; the solid equivalent of drizzle. (Also called granular snow.) They resemble snow pellets in external appearance, but are more fl
attened and elongated, and generally have diameters of less than 1 mm; they neither shatter nor bounce when they hit a hard surface. Descriptions of the physical structure of snow grains vary widely and include very fine, simple ice crystals; tiny, complex snow crystals; small, compact bundles of rime; and particles with a rime core and a fine glaze coating. It is agreed that snow grains usually fall in very small quantities, mostly from stratus clouds or from fog, and never in the form of a shower.
Precipitation in the form of very small, white opaque ice particles; they resemble snow pellets but are more flattened and elongated, with a diameter less than 1 mm; the solid equivalent of drizzle.
Minute, white and opaque grains of ice. When they hit hard ground, they do not bounce or shatter. They usually fall in very small quantities, and never in the form of a shower.
Precipitation of very small opaque white particles of ice which fall from a cloud and which are fairly flat or elongated with diameters generally less than 1 mm.
Frozen precipitation in the form of very small, white opaque grains of ice. The solid equivalent of drizzle. Their diameter is generally 1 mm. When grains hit hard ground, they do not bounce or shatte
r. They usually fall in very small quantities, mostly from Status clouds or fog and never in the form of a shower.
Snow ice forms by refreezing flooded snow, creating an ice layer that bonds firmly to the top surface of a floe. Ice formed by this process and makes a significant contribution to the total mass of An
tarctic sea ice. The snow cover of sea ice can become flooded by sea water via a number of mechanisms, in particular when the mass of snow becomes great enough to depress the ice/snow interface below sea level. The snow cover is porous and sea water can easily infiltrate from the sides of floes to form a slush layer at the ice/snow boundary. The snow may also become flooded by water rising up brine channels within the sea ice. With sufficiently cold temperatures this slush layer freezes to form snow ice.
The lowest atmospheric level or altitude where hydrometeors remain in the solid (ice) phase. This often occurs within two to three hundred meters below the freezing level (the lowest elevation in the
free atmosphere where the air temperature is 0
The line or zone on land that separates areas in which fallen snow disappears in summer from areas in which snow remains throughout the year. The altitude of the snow line is controlled by temperature
and the amount of snowfall (cf. Equilibrium line and Firn line).
The minimum elevation of snow lying on the ground or glacier surface; the snow line at the end of an ablation season marks a glacier's current equilibrium line.
In general, the outer boundary of a snow-covered area. It has at least two specific applications: 1) the actual lower limit of the snow cap on high terrain at any given time; 2) the ever-changing equa
torward limit of snow cover, particularly in the Northern Hemisphere winter.
Altitudinal or latitudinal limit separating zones where snow does not melt during the summer season from areas in which it does. Similar to the concept of firm limit except that it is not limited to g
laciers.
(1) Climatic snow-line: lowest altitude of continuous snow cover in high mountainous areas in summer. (2) Orographic snow-line: lowest altitude at which isolated patches of snow protected from melting
by orographic conditions persist in summer.
In general the outer boundary of a snow covered area. This may be the ever-changing latitudinal limit of snow cover, particularly in the Northern Hemisphere winter, or the lower limit in altitude of t
he permanent snow cover in mountainous terrain. The latter strongly depends on the aspect of slope. Snowline should not be confused with snow level.
(1) Climatic snowline: lowest altitude of a continuous layer of snow on the high mountains in summer. (2) Orographic snowline: lowest altitude at which snow persists on the land surface as isolated co
verings on the mountains in summer.