snow-on-the-mountain: see spurge.

snow plant: see Indian pipe.

snow line, altitude above which or latitude beyond which snow does not melt in summer (usually called the permanent snow line), or, in winter, the line to which snow extends at a given point in time. Factors affecting the location of the snow line are the quantity of snowfall, the steepness of the slope on which snow rests, the exposure of an area to the sun and prevailing winds, the type and velocity of the winds, and the presence or absence of large bodies of water. The level of the snow line is much lower in winter than in summer. It is also affected by distance from the equator, along which it is found at an altitude of c.3 mi (5 km); in polar regions it is at sea level.

snow, precipitation formed by the sublimation of water vapor into solid crystals at temperatures below freezing. Sublimation resulting in the formation of snow takes place about a dust particle, as in the formation of raindrops. Snowflakes form symmetrical (hexagonal) crystals, sometimes matted together if they descend through air warmer than that of the cloud in which they originated. Apparently, no two snow crystals are alike; they differ from each other in size, lacy structure, and surface markings. Snowfall, reduced to its liquid equivalent, is usually included in statistics on rainfall; the factors determining snowfall are similar to those affecting rainfall. On an average, 10 in. (25 cm) of snow is equivalent to 1 in. (2.5 cm) of rain. In the United States the average snowfall is about 28 in. (71 cm) per winter; the record is 1,140 in. (2,896 cm) at Mt. Baker in Washington state during the snow season of 1998-99. Snow that piles up on slopes may suddenly slide downward in an avalanche. A glacier consists of ice that was formed from compacted snow. Snow serves as an insulating blanket, lessening to some extent the extremes of temperature fluctuation to which the soil is subjected, but it also brings about a rapid cooling of the overlying atmosphere, giving rise to polar air masses. Snow lessens loss of water by dormant plants. The sudden melting of snow is a primary cause of floods. Snow necessitates the building of snowsheds over rail lines and highways in certain mountain localities where a heavy fall is likely to impede travel; the use of snowplows to clear sidewalks, streets, and roads; the use of snow fences to prevent drifting over roads; and the use of skis, snowshoes, toboggans, snowmobiles, and sleds for travel. It is a primary factor in the location of winter sports centers and so has great economic value to certain areas. In some ski resorts machines are used to make artificial snow. As in the case of rainfall, snowfall has been produced artificially by introducing dry-ice pellets into supercooled clouds, that is, clouds containing unfrozen water droplets at temperatures below freezing.

Snow, Lorenzo, 1814-1901, American Mormon leader, b. Mantua, Ohio, studied at Oberlin College. Entering the Church of Jesus Christ of Latter-day Saints (1836), Snow became an apostle in 1849. Upon his return from missionary work abroad, he settled in Utah, where, at Brigham, he established (1864) a mercantile and manufacturing cooperative. In 1889 he was made president of the Twelve Apostles and in 1898 president of the church. His works include an Italian translation of the Book of Mormon and The Only Way to Be Saved (1851).

Snow, John William, 1939-, U.S. government official and business executive, b. Toledo, Ohio. An economist and lawyer, he held Dept. of Transportation posts in the Nixon and Ford administrations including deputy undersecretary (1975-76) and administrator of the National Highway Safety Administratiom (1976-77). In 1977, Snow, an advocate of transportation-industry deregulaton, became a lobbyist and vice president with the Chessie System Railway, which merged with the Seaboard Coast Line in 1980 to form the CSX Corp. He rose to become president (1988), chief executive officer (1989), and chairman (1991) of CSX and oversaw the railroad's purchase of 42% of Conrail, which was completed in 1999. From 2003 to 2006 Snow served secretary of the treasury under President George W. Bush.

Snow, C. P. (Charles Percy Snow, Baron Snow of Leicester), 1905-80, English author and physicist. Snow had an active, varied career, including several important positions in the British government. He served as technical director of the ministry of labor from 1940 to 1944; as civil service commissioner from 1945 to 1960; and as parliamentary secretary to the minister of technology from 1964 to 1966. As a novelist, Snow was particularly noted for his series of 11 related novels known collectively as Strangers and Brothers. The series traces the career of Lewis Eliot from his boyhood in a provincial town, through law school and years as a fellow at Cambridge, to an important government position; in many respects Eliot's career parallels that of Snow himself. Although the series has been read as a study of power, or as an analysis of the relationship between science and the community, it is primarily a perceptive and frequently moving delineation of changes in English life during the 20th cent. Among the novels in the series are Strangers and Brothers (1940), The Masters (1951), The New Men (1954), The Affair (1960), Corridors of Power (1964), and Last Things (1970). Snow's other novels include The Search (1934), In Their Wisdom (1974), and A Coat of Varnish (1979); Science and Government (1961), a collection of essays concerning the vocation of the scientist; biographical studies such as A Variety of Men (1967), The Realists (1978), and The Physicists (1981); and Public Affairs (1971), a collection of lectures about the benefits and dangers of technology. His 1959 Rede Lecture on The Two Cultures and the Scientific Revolution, lamenting the increasing gulf between "literary intellectuals" and "scientists," provoked widespread and heated debate. He was married to the novelist Pamela Hansford Johnson. Snow was knighted in 1957 and created baron (life peer) in 1964.

or ounce

Endangered species ( Uncia uncia;) of nocturnal long-haired cat that inhabits the high mountains of Central Asia and India. It is about 6 ft (1.8 m) long, including the 3-ft (1-m) tail, stands about 2 ft (0.5 m) tall, and weighs 60–120 lb (27–55 kg). Its dense, soft coat, consisting of an insulating undercoat and outer coat of 2-in. (5-cm) hairs, is pale grayish with dark rosettes and a dark streak along the spine. The whitish fur of the underparts may be 4 in. (10 cm) long. It preys on marmots, wild sheep and goats, birds, and other animals. It is hunted principally for the market in goods used in Asian traditional medicine.

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Solid form of water that crystallizes in the atmosphere and falls to the Earth, covering about 23percnt of the Earth's surface either permanently or temporarily. Snowflakes are formed by crystals of ice that generally have a hexagonal pattern. Snow cover has a significant effect on climate and on plant, animal, and human life. By increasing the reflection of solar radiation and interfering with the conduction of heat from the ground, it induces a cold climate. The low heat conduction protects small plants from the effects of the lowest winter temperatures; on the other hand, late disappearance of snow in the spring delays the growth of plants.

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later Baron Snow (of the City of Leicester)

(born Oct. 15, 1905, Leicester, Leicestershire, Eng.—died July 1, 1980, London) British novelist, scientist, and government administrator. Snow was a molecular physicist at the University of Cambridge for some 20 years and served as a scientific adviser to the British government. His 11-novel sequence Strangers and Brothers (1940–70), which analyzes bureaucratic man and the corrupting influence of power, includes The Masters (1951), The New Men (1954), and Corridors of Power (1964). The Two Cultures and the Scientific Revolution (1959) and later nonfiction works deal with the cultural separation between practitioners of science and literature.

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